Materiały źródłowe

• #1 Hairy Cell Leukemia: Practice Essentials, Pathophysiology, Epidemiology

  https://emedicine.medscape.com/article/200580-overview

  Hairy cell leukemia (HCL) is a chronic lymphoid leukemia, originally described in 1958 by Bouroncle and colleagues and named after the hairlike cytoplasmic projections seen on the surface of the abnormal B-cells. […] Hairy cell leukemia is recognized as a clonal B-cell malignancy, as identified by immunoglobulin gene rearrangements that result in a phenotype B-cell expression of surface antigens. […] The pathogenesis of HCL was clarified by the discovery of its underlying genetic cause, the BRAF V600E kinase-activating mutation, which is somatically and clonally present in almost all patients through the entire disease spectrum and clinical course. […] Accumulation of hairy cells in the bone marrow, liver, and spleen, with very little lymph node involvement, is characteristic of HCL.

• #2 Hairy cell leukemia – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hairy-cell-leukemia/diagnosis-treatment/drc-20372962

  Enlarged spleen […] To diagnose hairy cell leukemia, your health care provider may recommend: […] Blood tests. You might have a blood test to measure the levels of blood cells in your blood. This test is called a complete blood count (CBC) with differential. […] In hairy cell leukemia, a CBC test may show all levels of these cells are too low. […] Another type of blood test might involve looking at your blood under the microscope. This test can find hairy cell leukemia cells. This test is called a peripheral blood smear. […] Bone marrow biopsy. A bone marrow biopsy is a procedure to remove some of your bone marrow for testing. Your provider will remove a small amount of bone marrow from your hip area. This sample is used to look for hairy cell leukemia cells. […] Lab tests to analyze the leukemia cells. Hairy cell leukemia cells collected from your blood and bone marrow are tested in a lab. These tests look at the changes in the cells’ DNA. This helps your provider understand your prognosis and what treatments are best for you. […] Computerized tomography (CT) scan. A CT scan shows detailed images of the inside of your body. Your provider may order a CT scan to look for swelling in your spleen and your lymph nodes.

• #3 Hairy cell leukemia – Symptoms and causes – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hairy-cell-leukemia/symptoms-causes/syc-20372956

  Hairy cell leukemia might not cause symptoms. Sometimes a health care provider finds it by accident during a blood test for another condition. […] Make an appointment with your health care provider if you have any persistent signs and symptoms that worry you. […] Hairy cell leukemia begins in the white blood cells. The white blood cells help fight germs in the body. There are a few types of white blood cells. The white blood cells involved in hairy cell leukemia are called B cells. […] Hairy cell leukemia happens when B cells develop changes in their DNA. A cell’s DNA contains the instructions that tell a cell what to do. The changes tell the B cells to make a lot more B cells that don’t work right. […] Some studies found that people with hairy cell leukemia have an increased risk of other types of cancer. The other cancers include non-Hodgkin’s lymphoma, Hodgkin’s lymphoma and others. It’s not clear if the other cancers are caused by hairy cell leukemia or by cancer treatments.

• #4 Understanding Hairy Cell Leukemia — Hairy Cell Leukemia Foundation

  https://www.hairycellleukemia.org/hairy-cell-leukemia

  Patients with hairy cell leukemia may develop many different symptoms. A physician should use careful clinical judgement to accurately diagnose a patients disease. […] In early research carried out by Dr. Bertha Bouroncle, an enlarged spleen was found in more than 90% of patients with hairy cell leukemia. However, the finding of an enlarged spleen has become less common over the years due to the more frequent use of blood tests to diagnose hairy cell leukemia. […] Therefore, the failure to identify an enlarged spleen does not preclude the diagnosis of hairy cell leukemia. […] To find the cause of an enlarged spleen or the reason for an abnormal blood test, more investigations will need to be done, generally by a hematologist. […] The full blood count test will often show anemia (low red blood cell count that can predispose to fatigue), low white blood cell count (that can predispose to infection), and a low platelet count (that can predispose to bleeding).

• #5 Rare Clinical Symptoms in Hairy Cell Leukemia: An Overview

  https://www.mdpi.com/2072-6694/16/17/3054

  Diagnosis of hairy cell leukemia is based on the presence of hairy cells in bone marrow and peripheral blood as well as the characteristic immunophenotype. Moreover, in classic HCL, most patients present with a BRAF V600E mutation. The typical symptoms of classic hairy cell leukemia include pancytopenia, massive splenomegaly and increased risk of infection. […] Diagnosis is based on peripheral blood (PB) and bone marrow (BM) morphology, flow cytometry, immunophenotyping, immunohistochemistry and molecular studies. The majority of patients with HCL are asymptomatic at diagnosis and the disease is usually found incidentally during routine blood cell counts. The typical clinical presentation of classic HCL involves pancytopenia, monocytopenia, splenomegaly, constitutional symptoms and increased risk of infection.

• #6 Hairy Cell Leukemia Pathogenesis, Diagnosis, and Prognosis

  https://www.onclive.com/view/hairy-cell-leukemia-pathogenesis-diagnosis-prognosis

  The initial workup in a patient with suspected HCL is depicted in Table 2. Close evaluation of the peripheral blood smear, including a differential count, should be a part of the initial workup. Although leukemic cells are often rare, monocytopenia is a rather sensitive and specific finding in HCL detection. Hairy cells have an abundant pale blue cytoplasm, an oblong nucleus, a serrated cytoplasmic border, and hair-like/threadlike cytoplasmic extensions. Immunophenotyping of the leukemic cells is essential for establishing a diagnosis of HCL. Detection of monotypic B cells is an important step in identifying mature B-cell neoplasms, as these cells express only a single immunoglobulin species. Peripheral blood mononuclear cells in HCL exhibit light-chain restriction of either kappa- or lambda-expressing B cells. Diagnosis of the classical form of HCL is confirmed by bright positivity for CD11c, CD20, and CD22, and positivity for CD19, CD103, and CD123. The neoplastic cells are negatively stained for CD27 antigen but intensely stained for CD200 expression. Bone marrow aspirates may yield a dry tap, which is due to bone marrow fibrosis and loss of hematopoietic cells in patients with HCL. The extent of bone marrow infiltration can be ascertained via bone marrow trephine biopsy and aspirate. The extent of bone marrow involvement is determined by immunohistochemical stains for CD20, annexin-1A, tartrate-resistant acid phosphatase (TRAP), DBA.44, and VE1 (a stain for BRAF V600E). Presence of the BRAF V600E mutation differentiates classic HCL from other lymphoid neoplasms and thus has therapeutic implications. Therefore, highly sensitive molecular assays for the mutation should be used (eg, next-generation sequencing or allele-specific polymerase chain reaction), rather than less sensitive methods (eg, melting curve analysis, pyrosequencing, or Sanger sequencing). If these techniques are not available, however, then the application of VE1 immunohistochemical stain to the bone marrow biopsy may allow for detection of the BRAF V600E mutation.

• #7 Hairy cell leukemia – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/890

  Hairy cell leukemia (HCL) is an uncommon, indolent, mature B-cell neoplasm. It is characterized by symptoms of fatigue, a markedly enlarged spleen, pancytopenia, and a distinctive histologic appearance on peripheral blood smear and bone marrow biopsy. […] In symptomatic patients or those with worsening blood counts, treatment with purine analogs is recommended. […] HCL has a characteristic presentation of pancytopenia, splenomegaly, and hairy cells in the peripheral blood, bone marrow, and other hematopoietic organs. […] Key diagnostic factors include abdominal fullness or discomfort and splenomegaly. […] Other diagnostic factors include weakness and fatigue, unexplained weight loss, bruising and bleeding, pallor, recurrent infections, hepatomegaly, lymphadenopathy, neurologic findings, and associated systemic immunologic disorders.

• #8 Hairy cell leukemia – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/890

  Hairy cell leukemia (HCL) is an uncommon, indolent, mature B-cell neoplasm. It is characterized by symptoms of fatigue, a markedly enlarged spleen, pancytopenia, and a distinctive histologic appearance on peripheral blood smear and bone marrow biopsy. […] In symptomatic patients or those with worsening blood counts, treatment with purine analogs is recommended. […] HCL has a characteristic presentation of pancytopenia, splenomegaly, and hairy cells in the peripheral blood, bone marrow, and other hematopoietic organs. […] Key diagnostic factors include abdominal fullness or discomfort and splenomegaly. […] Other diagnostic factors include weakness and fatigue, unexplained weight loss, bruising and bleeding, pallor, recurrent infections, hepatomegaly, lymphadenopathy, neurologic findings, and associated systemic immunologic disorders.

• #9 Hairy cell leukemia – Symptoms, diagnosis and treatment | BMJ Best Practice US

  https://bestpractice.bmj.com/topics/en-us/890

  1st tests to order include CBC with differential, peripheral blood smear, bone marrow trephine biopsy and aspiration (morphology assessment), immunophenotyping (immunohistochemistry or flow cytometry), comprehensive metabolic panel, serum lactate dehydrogenase (LDH), and viral serology for hepatitis B and C. […] Tests to consider include molecular analysis (for BRAF V600E mutation or IGHV4-34 rearrangement) and CT chest, abdomen, and pelvis.

• #10 Hairy Cell Leukemia: Symptoms, Causes & Treatment

  https://my.clevelandclinic.org/health/diseases/23177-hairy-cell-leukemia

  Hairy cell leukemia is a rare type of blood cancer that happens when your bone marrow makes abnormal B-cells (B lymphocytes). […] Healthcare providers will ask when your symptoms started and take a medical history, including whether you have infections that keep coming back. Theyll also do a physical examination. They may feel (palpitate) your lymph nodes, spleen and liver for signs of swelling. […] They may refer you to a hematologist or medical oncologist for more tests that will lead to a diagnosis. These tests may include: Complete blood count (CBC) with differential: This test measures the number of red and white blood cells and platelets. The differential measures the different types of white blood cells. […] Peripheral blood smear: Pathologists examine blood cells under a microscope, looking for abnormal cells that have the tiny hair-like projections that give hairy cell leukemia its name.

• #11 Understanding Hairy Cell Leukemia — Hairy Cell Leukemia Foundation

  https://www.hairycellleukemia.org/hairy-cell-leukemia

  Patients with hairy cell leukemia may develop many different symptoms. A physician should use careful clinical judgement to accurately diagnose a patients disease. […] In early research carried out by Dr. Bertha Bouroncle, an enlarged spleen was found in more than 90% of patients with hairy cell leukemia. However, the finding of an enlarged spleen has become less common over the years due to the more frequent use of blood tests to diagnose hairy cell leukemia. […] Therefore, the failure to identify an enlarged spleen does not preclude the diagnosis of hairy cell leukemia. […] To find the cause of an enlarged spleen or the reason for an abnormal blood test, more investigations will need to be done, generally by a hematologist. […] The full blood count test will often show anemia (low red blood cell count that can predispose to fatigue), low white blood cell count (that can predispose to infection), and a low platelet count (that can predispose to bleeding).

• #12 Hairy cell leukemia – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hairy-cell-leukemia/diagnosis-treatment/drc-20372962

  Enlarged spleen […] To diagnose hairy cell leukemia, your health care provider may recommend: […] Blood tests. You might have a blood test to measure the levels of blood cells in your blood. This test is called a complete blood count (CBC) with differential. […] In hairy cell leukemia, a CBC test may show all levels of these cells are too low. […] Another type of blood test might involve looking at your blood under the microscope. This test can find hairy cell leukemia cells. This test is called a peripheral blood smear. […] Bone marrow biopsy. A bone marrow biopsy is a procedure to remove some of your bone marrow for testing. Your provider will remove a small amount of bone marrow from your hip area. This sample is used to look for hairy cell leukemia cells. […] Lab tests to analyze the leukemia cells. Hairy cell leukemia cells collected from your blood and bone marrow are tested in a lab. These tests look at the changes in the cells’ DNA. This helps your provider understand your prognosis and what treatments are best for you. […] Computerized tomography (CT) scan. A CT scan shows detailed images of the inside of your body. Your provider may order a CT scan to look for swelling in your spleen and your lymph nodes.

• #13 https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  Diagnosing hairy cell leukemia usually involves a series of tests, including blood tests and bone marrow tests. […] Your doctor needs to test your blood to help make a diagnosis. Your blood is sent to a lab for a complete blood count (CBC), which shows the number of red cells, white cells and platelets in your blood. If you have hairy cell leukemia, you’ll have lower than normal levels of red cells, platelets and normal white cells. Occasionally, the blood contains many hairy cells, which increases the total white cell count. However, levels of white cells called neutrophils and monocytes are still extremely low. […] Your doctor or oncologist (cancer specialist) tests your bone marrow. Bone marrow testing involves two steps usually done at the same time in a doctor’s office or a hospital: A bone marrow aspiration to remove a liquid marrow sample, A bone marrow biopsy to remove a small amount of bone filled with marrow.

• #14 https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  Diagnosing hairy cell leukemia usually involves a series of tests, including blood tests and bone marrow tests. […] Your doctor needs to test your blood to help make a diagnosis. Your blood is sent to a lab for a complete blood count (CBC), which shows the number of red cells, white cells and platelets in your blood. If you have hairy cell leukemia, you’ll have lower than normal levels of red cells, platelets and normal white cells. Occasionally, the blood contains many hairy cells, which increases the total white cell count. However, levels of white cells called neutrophils and monocytes are still extremely low. […] Your doctor or oncologist (cancer specialist) tests your bone marrow. Bone marrow testing involves two steps usually done at the same time in a doctor’s office or a hospital: A bone marrow aspiration to remove a liquid marrow sample, A bone marrow biopsy to remove a small amount of bone filled with marrow.

• #15 https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  Diagnosing hairy cell leukemia usually involves a series of tests, including blood tests and bone marrow tests. […] Your doctor needs to test your blood to help make a diagnosis. Your blood is sent to a lab for a complete blood count (CBC), which shows the number of red cells, white cells and platelets in your blood. If you have hairy cell leukemia, you’ll have lower than normal levels of red cells, platelets and normal white cells. Occasionally, the blood contains many hairy cells, which increases the total white cell count. However, levels of white cells called neutrophils and monocytes are still extremely low. […] Your doctor or oncologist (cancer specialist) tests your bone marrow. Bone marrow testing involves two steps usually done at the same time in a doctor’s office or a hospital: A bone marrow aspiration to remove a liquid marrow sample, A bone marrow biopsy to remove a small amount of bone filled with marrow.

• #16 Hairy Cell Leukemia Pathogenesis, Diagnosis, and Prognosis

  https://www.onclive.com/view/hairy-cell-leukemia-pathogenesis-diagnosis-prognosis

  The initial workup in a patient with suspected HCL is depicted in Table 2. Close evaluation of the peripheral blood smear, including a differential count, should be a part of the initial workup. Although leukemic cells are often rare, monocytopenia is a rather sensitive and specific finding in HCL detection. Hairy cells have an abundant pale blue cytoplasm, an oblong nucleus, a serrated cytoplasmic border, and hair-like/threadlike cytoplasmic extensions. Immunophenotyping of the leukemic cells is essential for establishing a diagnosis of HCL. Detection of monotypic B cells is an important step in identifying mature B-cell neoplasms, as these cells express only a single immunoglobulin species. Peripheral blood mononuclear cells in HCL exhibit light-chain restriction of either kappa- or lambda-expressing B cells. Diagnosis of the classical form of HCL is confirmed by bright positivity for CD11c, CD20, and CD22, and positivity for CD19, CD103, and CD123. The neoplastic cells are negatively stained for CD27 antigen but intensely stained for CD200 expression. Bone marrow aspirates may yield a dry tap, which is due to bone marrow fibrosis and loss of hematopoietic cells in patients with HCL. The extent of bone marrow infiltration can be ascertained via bone marrow trephine biopsy and aspirate. The extent of bone marrow involvement is determined by immunohistochemical stains for CD20, annexin-1A, tartrate-resistant acid phosphatase (TRAP), DBA.44, and VE1 (a stain for BRAF V600E). Presence of the BRAF V600E mutation differentiates classic HCL from other lymphoid neoplasms and thus has therapeutic implications. Therefore, highly sensitive molecular assays for the mutation should be used (eg, next-generation sequencing or allele-specific polymerase chain reaction), rather than less sensitive methods (eg, melting curve analysis, pyrosequencing, or Sanger sequencing). If these techniques are not available, however, then the application of VE1 immunohistochemical stain to the bone marrow biopsy may allow for detection of the BRAF V600E mutation.

• #17 Hairy cell leukemia (HZL) | MLL

  https://www.mll.com/en/mature-b-cell-neoplasms/hairy-cell-leukemia

  Based on the current guidelines and the current state of research, there are different diagnostic recommendations for patients with hairy cell leukemia. […] We have summarized the most important information about the classification and diagnostic methods at MLL. […] In smears of peripheral blood or bone marrow in HZL, neoplastic cells are small to medium-sized, with oval to indented, „kidney-shaped” nuclei with pale, glassy chromatin that is less clumped than that of normal lymphocytes. […] Examination of the bone marrow aspirate and especially the -biopsy specimen is essential to determine the extent of bone marrow infiltration and to validate the diagnosis. […] Specific to hairy cell leukemia is the immunohistochemically detectable expression of annexin A1 (ANXA1), this is not found in any other mature B cell neoplasia.

• #18 https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  https://www.lls.org/leukemia/hairy-cell-leukemia/diagnosis

  A hematopathologist examines samples of your blood and marrow to confirm a diagnosis. A hematopathologist is a specialist who studies blood cell diseases by looking at samples of blood and marrow cells and other tissues. […] Hairy cells can be hard to find in the blood but can often be identified with careful searching. The hematologist stains dried marrow cells under a lighted microscope to identify whether hairy cells are present. The marrow cells often have a characteristic pattern to them. However, a firm diagnosis requires immunophenotyping performed on the blood or marrow cells. Immunophenotyping looks for a characteristic marker (antigen) on the surfaces of lymphocytes to determine if they form a certain pattern that indicates hairy cell leukemia. Flow cytometry is one type of test used for immunophenotyping.

• #19 Pathology Outlines – Hairy cell leukemia

  https://www.pathologyoutlines.com/topic/lymphomahcl.html

  Hairy cell leukemia (HCL) is a rare, indolent lymphoproliferative neoplasm of mature B cells with a distinct clinical presentation that includes peripheral blood cytopenias, splenomegaly and a small number of circulating neoplastic cells with hair-like cytoplasmic projections […] Diagnosis is based on peripheral blood and bone marrow morphology, flow cytometry immunophenotyping, immunohistochemistry and molecular studies […] CBC and differential count: pancytopenia and monocytopenia […] Peripheral blood smear morphology: circulating neoplastic hairy cells are present but at a low frequency and they can be difficult to identify.

• #20 Diagnosis of hairy cell leukemia – Holland-Frei Cancer Medicine – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK13250/

  Diagnosis of hairy cell leukemia […] The best approach to establishing the diagnosis of hairy cell leukemia is to carefully examine blood and bone marrow biopsy specimens to identify cells with the morphologic features of hairy cells and to demonstrate that the neoplastic cells have an antigenic profile that is characteristic for hairy cell leukemia. […] Because hairy cells are frequently scarce in the blood and because increased bone marrow reticulin fibers usually prevent aspiration of marrow spicules, the bone marrow biopsy specimen is often the most reliable for confirming the diagnosis of hairy cell leukemia. […] Although the morphologic features of hairy cell leukemia in the blood and marrow are usually characteristic, determination of the immunophenotype of the neoplastic cells is essential to confirm the diagnosis and to distinguish hairy cell leukemia from other lymphoproliferative lesions with which it can be confused. […] Tartrate-resistant acid phosphatase (TRAP) activity is present in the leukemic cells of most patients with hairy cell leukemia, and its detection with cytochemical techniques has been a traditional test for substantiating the diagnosis. […] Recently, however, monoclonal antibodies to TRAP that work well in biopsy sections have become available, and when used in conjunction with antibodies for CD20 and/or DBA.44, they have proved to be useful in the diagnosis of hairy cell leukemia.

• #21 Understanding Hairy Cell Leukemia — Hairy Cell Leukemia Foundation

  https://www.hairycellleukemia.org/hairy-cell-leukemia

  The peripheral blood smear will often show a reduction or absence of a type of white blood cells called monocytes, and may document the appearance of cells with a pale cytoplasm with a hairy rim. […] Immunophenotyping is a test that helps identify the hairy cells with the use of markers (so called clusters of differentiation or CD) by monoclonal antibodies, each of which has a number or a name and will be expressed on all the malignant cells. […] A bone marrow biopsy is performed by using a needle to take a sample of bone near the rear area of the hip. […] An accurate diagnosis is necessary to determine the correct treatment for each patient. It may be helpful to seek consultation at a Center of Excellence.

• #22 Hairy cell leukemia 2018: Update on diagnosis, risk‐stratification, and treatment

  https://pmc.ncbi.nlm.nih.gov/articles/PMC5698705/

  In the international consensus guidelines, trephine bone marrow biopsy and/or aspiration has been emphasized to appreciate the tumor infiltration degree and to help diagnose complex cases (immunostaining with CD20, CD76 and Annexin A1). […] The BRAFV600E mutation is now considered as the molecular hallmark of the disease and represents a novel diagnostic possibility and option for therapeutic targeting of BRAF, using BRAF inhibitors. Absence of the BRAF gene mutation was reported in up to 10% to 20% of patients with HCL and could constitute a subgroup of HCL patients with a poor prognosis. […] The use of a VE1 antibody that is specific to BRAFV600E mutated cells could also represent a simple and first approach in clinical practice to detect MRD.

• #23 Hairy-Cell Leukemia — Onkopedia

  https://www.onkopedia.com/en/onkopedia/guidelines/hairy-cell-leukemia

  For examples of microscopic diagnostics, see eLearning Curriculum Hematology (eLCH), https://ehaematology.com/. […] The diagnostic algorithm is divided into basic and special tests, see Table 1. Despite the typical lymphocytopenia, hair cells are detectable in the peripheral blood of most patients, the relative proportion is usually below 10%, often below 1%. Standard in diagnostics is multiparametric immunophenotyping with at least 4 fluorescent dyes and a sensitivity of 1/1,000 cells. […] Standard diagnostic procedure is bone marrow aspiration and biopsy, for characteristic morphology see chapter 2. 1. The detection of a (small) subpopulation of lymphoid cells in peripheral blood with the immunophenotype of hair cells is not sufficient for diagnosis. HCL is one of the hematologic diseases in which punctio sicca frequently occurs, in this case due to fiber formation in the bone marrow.

• #24 Final Diagnosis — Case 691

  https://path.upmc.edu/cases/case691/dx.html

  FINAL DIAGNOSIS: HAIRY CELL LEUKEMIA […] The diagnosis is best made on a bone marrow biopsy as an increase in reticulin fibers is present with hairy cell infiltrates in the bone marrow and often results in a „dry tap”, as in this case. […] Recognizing the variability of immunophenotype and correlating with morphologic and clinical features are essential for establishing an accurate diagnosis of hairy cell leukemia. […] In this case, although the lymphoid cells lacked expression of CD103 by flow cytometry, the immunohistochemical stains along with the morphologic findings and results of flow cytometry studies were compatible with a diagnosis of hairy cell leukemia. […] The lack of CD103 expression in a small B-cell lymphoid neoplasm with hairy cell features of the lymphoid cells should not exclude a diagnosis of HCL. This case stresses the importance of ancillary studies, such as immunohistochemical staining with Annexin A1, in formulating this diagnosis.

• #25 Hairy cell leukemia, an uncommon B-cell lymphoid neoplasia | Medicina Universitaria

  https://www.elsevier.es/en-revista-medicina-universitaria-304-articulo-hairy-cell-leukemia-an-uncommon-S1665579616300151

  Some HCL histopathologic and immunophenotypic characteristics are the following: Lymphocyte flow cytometry in peripheral blood or bone marrow with CD19, CD20, FMC7, CD11c, CD103, CD25, HC2, CD22, sIg, CD79a and CD123 expressions, with four being the main and specific markers: CD11c, CD103, CD25 and CD123. Commonly negative markers are CD5, CD23, CD10, CD79b and CD27. A strong expression for CD200 is characteristic of HCL and may be useful in the diagnosis of difficult cases. Bone marrow aspiration with a needle may be difficult to obtain and is frequently unproductive or dry. In a bone marrow biopsy, we can observe fibrosis, with a cellular fried-egg look caused by the wide spaces between nuclei and abundant cytoplasm. Immunohistochemistry analyses for CD20 and TRAP (tartrate resistant acid phosphatase), DBA-4 and annexin A1 are conducted, which are characteristically positive.

• #26 Hairy cell leukemia – Wikipedia

  https://en.wikipedia.org/wiki/Hairy_cell_leukemia

  The diagnosis of HCL may be suggested by abnormal results on a complete blood count (CBC), but additional testing is necessary to confirm the diagnosis. A CBC normally shows low counts for white blood cells, red blood cells, and platelets in HCL patients. However, if large numbers of hairy cells are in the blood stream, then normal or even high lymphocyte counts may be found. […] Most patients require a bone-marrow biopsy for final diagnosis. The bone marrow biopsy is used both to confirm the presence of HCL and also the absence of any additional diseases, such as Splenic marginal zone lymphoma or B-cell prolymphocytic leukemia. The bone marrow in HCL may show a diffuse infiltration of leukemic cells or an interstitial infiltration with partial preservation of fat and hematopoietic stem cells.

• #27 Diagnosis of hairy cell leukemia – Holland-Frei Cancer Medicine – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK13250/

  Diagnosis of hairy cell leukemia […] The best approach to establishing the diagnosis of hairy cell leukemia is to carefully examine blood and bone marrow biopsy specimens to identify cells with the morphologic features of hairy cells and to demonstrate that the neoplastic cells have an antigenic profile that is characteristic for hairy cell leukemia. […] Because hairy cells are frequently scarce in the blood and because increased bone marrow reticulin fibers usually prevent aspiration of marrow spicules, the bone marrow biopsy specimen is often the most reliable for confirming the diagnosis of hairy cell leukemia. […] Although the morphologic features of hairy cell leukemia in the blood and marrow are usually characteristic, determination of the immunophenotype of the neoplastic cells is essential to confirm the diagnosis and to distinguish hairy cell leukemia from other lymphoproliferative lesions with which it can be confused. […] Tartrate-resistant acid phosphatase (TRAP) activity is present in the leukemic cells of most patients with hairy cell leukemia, and its detection with cytochemical techniques has been a traditional test for substantiating the diagnosis. […] Recently, however, monoclonal antibodies to TRAP that work well in biopsy sections have become available, and when used in conjunction with antibodies for CD20 and/or DBA.44, they have proved to be useful in the diagnosis of hairy cell leukemia.

• #28 Hairy Cell Leukemia (HCL) | Flow Cytometry

  https://wiki.clinicalflow.com/hairy-cell-leukemia-hcl

  Hairy cell leukemia is a mature B cell neoplasm. It is usually classified as a sub-type of chronic lymphoid leukemia (CLL) for convenience. […] This disease is rare, with fewer than 1 in 10,000 people being diagnosed with HCL during their lives. […] Abnormal white blood cells bearing hair-like projections from the cytoplasm are seen on blood film examination or bone marrow biopsy. […] Hairy cells are larger than normal and positive for CD19, CD20, CD22, CD11c, CD25, CD103, and FMC7. […] Cytochemistry: Tartrate resistant acid phosphatase is positive in HCL. […] FC shows increased SSC placing the leukemic cells in the 'monocytic’ region of the CD45 vs SSC plot. These cells are bright CD20, CD11c and surface immunoglobulins (kappa or lambda).

• #29 Diagnosis of hairy cell leukemia – Holland-Frei Cancer Medicine – NCBI Bookshelf

  https://www.ncbi.nlm.nih.gov/books/NBK13250/

  Diagnosis of hairy cell leukemia […] The best approach to establishing the diagnosis of hairy cell leukemia is to carefully examine blood and bone marrow biopsy specimens to identify cells with the morphologic features of hairy cells and to demonstrate that the neoplastic cells have an antigenic profile that is characteristic for hairy cell leukemia. […] Because hairy cells are frequently scarce in the blood and because increased bone marrow reticulin fibers usually prevent aspiration of marrow spicules, the bone marrow biopsy specimen is often the most reliable for confirming the diagnosis of hairy cell leukemia. […] Although the morphologic features of hairy cell leukemia in the blood and marrow are usually characteristic, determination of the immunophenotype of the neoplastic cells is essential to confirm the diagnosis and to distinguish hairy cell leukemia from other lymphoproliferative lesions with which it can be confused. […] Tartrate-resistant acid phosphatase (TRAP) activity is present in the leukemic cells of most patients with hairy cell leukemia, and its detection with cytochemical techniques has been a traditional test for substantiating the diagnosis. […] Recently, however, monoclonal antibodies to TRAP that work well in biopsy sections have become available, and when used in conjunction with antibodies for CD20 and/or DBA.44, they have proved to be useful in the diagnosis of hairy cell leukemia.

• #30 Understanding Hairy Cell Leukemia — Hairy Cell Leukemia Foundation

  https://www.hairycellleukemia.org/hairy-cell-leukemia

  The peripheral blood smear will often show a reduction or absence of a type of white blood cells called monocytes, and may document the appearance of cells with a pale cytoplasm with a hairy rim. […] Immunophenotyping is a test that helps identify the hairy cells with the use of markers (so called clusters of differentiation or CD) by monoclonal antibodies, each of which has a number or a name and will be expressed on all the malignant cells. […] A bone marrow biopsy is performed by using a needle to take a sample of bone near the rear area of the hip. […] An accurate diagnosis is necessary to determine the correct treatment for each patient. It may be helpful to seek consultation at a Center of Excellence.

• #31 Hairy cell leukemia 2018: Update on diagnosis, risk‐stratification, and treatment

  https://pmc.ncbi.nlm.nih.gov/articles/PMC5698705/

  Diagnosis of HCL is based on morphological evidence of hairy cells, an HCL immunologic score of 3 or 4 based on the CD11C, CD103, CD123, and CD25 expression, the trephine biopsy which makes it possible to specify the degree of tumoral medullary infiltration and the presence of BRAF V600E somatic mutation. […] The HCL immunophenotypic profile is characterized by the clonal expansion of Bcells with bright CD19, CD20, CD22, and CD200 expression. Hairy cells are usually negative or dim for CD5, CD23, CD10, CD79b, and CD27 but positive for CD11c, CD103, CD123, and CD25. An immunological score was proposed with one point given to each of the last four markers when they are expressed and no point when they are not expressed. A score of 3 or 4 is observed in 98% of HCL cases, whereas in other HCLlike disorders, the score is usually low: 0 or 1.

• #32 Rare Clinical Symptoms in Hairy Cell Leukemia: An Overview

  https://www.mdpi.com/2072-6694/16/17/3054

  The characteristic immunophenotype of classic HCL cells includes the co-expression of CD19, CD20, CD11c, CD25, CD103, CD200, FMC7 and CD123. The unique criterion for the diagnosis of HCL is the co-expression of CD103, CD25 and CD11c. […] Diagnosis and treatment evaluation of bone lesions is based on computed tomography (CT) and positron emission tomography (PET). […] A lung biopsy for histological examination is indicated in patients with pulmonary symptoms if antibiotics and antifungal treatment are not effective. […] In HCL patients, CNS involvement is typically indicated by confusion, aphasia, headache, meningeal syndrome, motor ataxia, dizziness, weakness, confusion, slurred speech, frequent falls, facial droop, fatigue, blurry vision and acute delusional symptoms. […] Diagnosis of leukemia cutis is performed based on the histopathology of skin biopsy and the immunophenotyping of neoplastic cells. Skin biopsy and immunophenotyping must be performed in all patients with suspicion of leukemia cutis. […] Diagnosis is based on peripheral blood (PB) and bone marrow (BM) morphology, flow cytometry, immunophenotyping, immunohistochemistry and molecular studies.

• #33 Hairy cell leukemia 2018: Update on diagnosis, risk‐stratification, and treatment

  https://pmc.ncbi.nlm.nih.gov/articles/PMC5698705/

  Diagnosis of HCL is based on morphological evidence of hairy cells, an HCL immunologic score of 3 or 4 based on the CD11C, CD103, CD123, and CD25 expression, the trephine biopsy which makes it possible to specify the degree of tumoral medullary infiltration and the presence of BRAF V600E somatic mutation. […] The HCL immunophenotypic profile is characterized by the clonal expansion of Bcells with bright CD19, CD20, CD22, and CD200 expression. Hairy cells are usually negative or dim for CD5, CD23, CD10, CD79b, and CD27 but positive for CD11c, CD103, CD123, and CD25. An immunological score was proposed with one point given to each of the last four markers when they are expressed and no point when they are not expressed. A score of 3 or 4 is observed in 98% of HCL cases, whereas in other HCLlike disorders, the score is usually low: 0 or 1.

• #34 A Differential Diagnosis of Hairy Cell Leukemia

  https://www.onclive.com/view/a-differential-diagnosis-of-hairy-cell-leukemia

  For most patients a bone marrow biopsy is required to make the diagnosis of hairy cell leukemia because the leukemic cells do not typically circulate in the peripheral blood. […] The differential diagnosis of course includes variant hairy cell leukemia, which is typically CD25-negative and CD123-negative, as well as splenic marginal zone lymphoma, which may have hairy like projection and splenic diffuse red pulp lymphoma. […] For classical hairy cell leukemia, the major molecular test is typical BRAF V600E mutation testing, which can be done by immunohistochemical stains on the bone marrow biopsy or by PCR [polymerase chain reaction]. […] For variant hairy cell leukemia, additional testing that can be helpful would include MAP2K1 mutation testing, as well as abnormalities of p53, which are present in about 40% of patients and can portend worse prognosis.

• #35 Hairy cell leukemia variant: the importance of differential diagnosis | Hematology, Transfusion and Cell Therapy

  https://www.htct.com.br/en-hairy-cell-leukemia-variant-importance-articulo-S1516848415000201

  Classic hairy cell leukemia, hairy cell leukemia variant, and SMZL share some common features, including malignant lymphocytic infiltration in bone marrow and peripheral blood, splenomegaly, and B lymphocytes with a similar immunophenotype. Unlike classic hairy cell leukemia, the variant form affects older individuals. Anemia and/or thrombocytopenia and leukocytosis are common at diagnosis of hairy cell leukemia variant, while pancytopenia, granulocytopenia, and monocytopenia are more common in classic hairy cell leukemia. The patient in this study presented with anemia, thrombocytopenia, and mild leukocytosis due to monocytosis, eosinophilia and the presence of pathological lymphocytes. […] Immunophenotyping by flow cytometry contributes to differential diagnosis, although it must also be associated with immunohistochemistry and clinical data. Classic hairy cell leukemia cells are always positive for CD25 and CD103 and hairy cell leukemia variant cells are always negative for CD25 and occasionally positive for CD103. In SMZL, on the other hand, CD103 is negative and CD25 may be positive or negative. Classic hairy cell leukemia and the variant form are also differentiated by the expression of CD123, which is positive in the classic form and negative in the variant form. Evaluation of immunoglobulin heavy chain isotype expression is another way to possibly differentiate hairy cell leukemia variant from SMZL. An unusual feature of hairy cell leukemia variant, not typically observed in other B-cell lymphoproliferative disorders, is the expression of pre-switched IgM/IgD and post-switched IgG/IgA immunoglobulins by the same cells in approximately 40% of cases.

• #36 Hairy cell leukemia 2018: Update on diagnosis, risk‐stratification, and treatment

  https://pmc.ncbi.nlm.nih.gov/articles/PMC5698705/

  In the international consensus guidelines, trephine bone marrow biopsy and/or aspiration has been emphasized to appreciate the tumor infiltration degree and to help diagnose complex cases (immunostaining with CD20, CD76 and Annexin A1). […] The BRAFV600E mutation is now considered as the molecular hallmark of the disease and represents a novel diagnostic possibility and option for therapeutic targeting of BRAF, using BRAF inhibitors. Absence of the BRAF gene mutation was reported in up to 10% to 20% of patients with HCL and could constitute a subgroup of HCL patients with a poor prognosis. […] The use of a VE1 antibody that is specific to BRAFV600E mutated cells could also represent a simple and first approach in clinical practice to detect MRD.

• #37 Hairy Cell Leukemia: Practice Essentials, Pathophysiology, Epidemiology

  https://emedicine.medscape.com/article/200580-overview

  Hairy cell leukemia (HCL) is a chronic lymphoid leukemia, originally described in 1958 by Bouroncle and colleagues and named after the hairlike cytoplasmic projections seen on the surface of the abnormal B-cells. […] Hairy cell leukemia is recognized as a clonal B-cell malignancy, as identified by immunoglobulin gene rearrangements that result in a phenotype B-cell expression of surface antigens. […] The pathogenesis of HCL was clarified by the discovery of its underlying genetic cause, the BRAF V600E kinase-activating mutation, which is somatically and clonally present in almost all patients through the entire disease spectrum and clinical course. […] Accumulation of hairy cells in the bone marrow, liver, and spleen, with very little lymph node involvement, is characteristic of HCL.

• #38 Hairy Cell Leukemia Differential Diagnoses

  https://emedicine.medscape.com/article/200580-differential

  Hairy cell leukemia (HCL) must be differentiated from other other peripheral small B-cell lymphoid neoplasms, including hairy cell leukemia variant (HCLV), HCL expressing IGHV4-34, and splenic diffuse red pulp lymphoma (SDRPL). While those neoplasms are histologically similar to classic HCL, they have a more aggressive clinical course and are less likely to respond to purine analog therapy. […] Testing for the BRAF V600E mutation allows for a genetics-based differential diagnosis between HCL and HCL-like tumors, as BRAF V600E is absent in other B-cell neoplasms. […] Other problems to be considered in the differential diagnosis of hairy cell leukemia include the following: Primary myelofibrosis, Chronic lymphocytic leukemia, Low-grade lymphoma, Myelosclerosis, Pancytopenia and marrow fibrosis, Prolymphocytic leukemia, Splenic marginal zone lymphoma, Systemic mastocytosis.

• #39 Hairy-Cell Leukemia — Onkopedia

  https://www.onkopedia.com/en/onkopedia/guidelines/hairy-cell-leukemia

  Molecular genetic testing for BRAF V600E mutation is recommended to confirm the diagnosis and to differentiate BRAF V600E from other indolent non-Hodgkin lymphomas and HCL. The detection of a BRAF V600E mutation is treatment-guiding for the option of using a BRAF inhibitor. […] Basic and special examinations are also distinguished in the course of the disease, see Table 2. […] In the context of clinical trials, the determination of minimal residual disease (MRD) by immunophenotypic and/or molecular genetic methods is used. It allows earlier assessment of treatment response and may have prognostic relevance. […] Two forms of HCL are distinguished, the so-called classic HCL and the variant. […] The differential diagnosis of cytopenia and splenomegaly is extensive. […] Prognosis has improved markedly since 1980. About 70% of patients with HCL have a normal life expectancy. The response to systemic therapy with purine analogs is crucial. Patients with complete hematologic remission have significantly longer progression-free survival than patients with partial hematologic remission.

• #40 Hairy Cell Leukemia Pathogenesis, Diagnosis, and Prognosis

  https://www.onclive.com/view/hairy-cell-leukemia-pathogenesis-diagnosis-prognosis

  The initial workup in a patient with suspected HCL is depicted in Table 2. Close evaluation of the peripheral blood smear, including a differential count, should be a part of the initial workup. Although leukemic cells are often rare, monocytopenia is a rather sensitive and specific finding in HCL detection. Hairy cells have an abundant pale blue cytoplasm, an oblong nucleus, a serrated cytoplasmic border, and hair-like/threadlike cytoplasmic extensions. Immunophenotyping of the leukemic cells is essential for establishing a diagnosis of HCL. Detection of monotypic B cells is an important step in identifying mature B-cell neoplasms, as these cells express only a single immunoglobulin species. Peripheral blood mononuclear cells in HCL exhibit light-chain restriction of either kappa- or lambda-expressing B cells. Diagnosis of the classical form of HCL is confirmed by bright positivity for CD11c, CD20, and CD22, and positivity for CD19, CD103, and CD123. The neoplastic cells are negatively stained for CD27 antigen but intensely stained for CD200 expression. Bone marrow aspirates may yield a dry tap, which is due to bone marrow fibrosis and loss of hematopoietic cells in patients with HCL. The extent of bone marrow infiltration can be ascertained via bone marrow trephine biopsy and aspirate. The extent of bone marrow involvement is determined by immunohistochemical stains for CD20, annexin-1A, tartrate-resistant acid phosphatase (TRAP), DBA.44, and VE1 (a stain for BRAF V600E). Presence of the BRAF V600E mutation differentiates classic HCL from other lymphoid neoplasms and thus has therapeutic implications. Therefore, highly sensitive molecular assays for the mutation should be used (eg, next-generation sequencing or allele-specific polymerase chain reaction), rather than less sensitive methods (eg, melting curve analysis, pyrosequencing, or Sanger sequencing). If these techniques are not available, however, then the application of VE1 immunohistochemical stain to the bone marrow biopsy may allow for detection of the BRAF V600E mutation.

• #41 Hairy cell leukemia 2018: Update on diagnosis, risk‐stratification, and treatment

  https://pmc.ncbi.nlm.nih.gov/articles/PMC5698705/

  In the international consensus guidelines, trephine bone marrow biopsy and/or aspiration has been emphasized to appreciate the tumor infiltration degree and to help diagnose complex cases (immunostaining with CD20, CD76 and Annexin A1). […] The BRAFV600E mutation is now considered as the molecular hallmark of the disease and represents a novel diagnostic possibility and option for therapeutic targeting of BRAF, using BRAF inhibitors. Absence of the BRAF gene mutation was reported in up to 10% to 20% of patients with HCL and could constitute a subgroup of HCL patients with a poor prognosis. […] The use of a VE1 antibody that is specific to BRAFV600E mutated cells could also represent a simple and first approach in clinical practice to detect MRD.

• #42 Hairy cell leukemia, an uncommon B-cell lymphoid neoplasia | Medicina Universitaria

  https://www.elsevier.es/en-revista-medicina-universitaria-304-articulo-hairy-cell-leukemia-an-uncommon-S1665579616300151

  Andrulis et al. directed a study where the efficiency of the VE1 antibody for BRAF V600E detection was reported, along with HCL identification in other entities. Moreover, a study conducted by Uppal et al. found a sensitivity of 88% and a specificity of 97% to detect this mutation with the mentioned antibody.

• #43 Hairy cell leukemia 2018: Update on diagnosis, risk‐stratification, and treatment

  https://pmc.ncbi.nlm.nih.gov/articles/PMC5698705/

  In the international consensus guidelines, trephine bone marrow biopsy and/or aspiration has been emphasized to appreciate the tumor infiltration degree and to help diagnose complex cases (immunostaining with CD20, CD76 and Annexin A1). […] The BRAFV600E mutation is now considered as the molecular hallmark of the disease and represents a novel diagnostic possibility and option for therapeutic targeting of BRAF, using BRAF inhibitors. Absence of the BRAF gene mutation was reported in up to 10% to 20% of patients with HCL and could constitute a subgroup of HCL patients with a poor prognosis. […] The use of a VE1 antibody that is specific to BRAFV600E mutated cells could also represent a simple and first approach in clinical practice to detect MRD.

• #44 A Differential Diagnosis of Hairy Cell Leukemia

  https://www.onclive.com/view/a-differential-diagnosis-of-hairy-cell-leukemia

  For most patients a bone marrow biopsy is required to make the diagnosis of hairy cell leukemia because the leukemic cells do not typically circulate in the peripheral blood. […] The differential diagnosis of course includes variant hairy cell leukemia, which is typically CD25-negative and CD123-negative, as well as splenic marginal zone lymphoma, which may have hairy like projection and splenic diffuse red pulp lymphoma. […] For classical hairy cell leukemia, the major molecular test is typical BRAF V600E mutation testing, which can be done by immunohistochemical stains on the bone marrow biopsy or by PCR [polymerase chain reaction]. […] For variant hairy cell leukemia, additional testing that can be helpful would include MAP2K1 mutation testing, as well as abnormalities of p53, which are present in about 40% of patients and can portend worse prognosis.

• #45 Hairy cell leukemia (HZL) | MLL

  https://www.mll.com/en/mature-b-cell-neoplasms/hairy-cell-leukemia

  Chromosomal analysis is not obligatory in the diagnosis of hairy cell leukemia. […] Like chromosomal analysis, this test is not mandatory for the diagnosis of HZL. […] In hairy cell leukemia, the V600E mutation in the BRAF gene occurs in over 95% of patients, but extremely rarely in other mature B-cell neoplasms. […] This can greatly facilitate the differentiation of hairy cell leukemia from other lymphomas. […] For cases without a detectable BRAF mutation but with a classic HZL immunophenotype, there appears to be an association with the IGHV4-34 gene. […] However, because these cases show overlap with SBLPN cases, it is not clear whether MAPK1-mutated HCL cases exist.

• #46 Hairy cell leukaemia | Lymphoma Action

  https://lymphoma-action.org.uk/types-lymphoma/hairy-cell-leukaemia

  Hairy cell leukaemia can sometimes be diagnosed using blood tests. These typically show low blood counts together with abnormal hairy lymphocytes in your bloodstream. The number of hairy cells in the blood can be very low and sometimes difficult to identify. You are likely to have a bone marrow biopsy to check for abnormal cells in your bone marrow. […] An expert lymphoma pathologist looks at your blood and biopsy samples under a microscope. They run specialised tests on the abnormal cells to find out if they have certain genetic changes or make particular proteins. […] Your doctor will also examine you to check for other signs of hairy cell leukaemia such as a swollen spleen or liver. You might have a scan, such as a CT scan or ultrasound scan, to see if your spleen is enlarged or if you have any swollen lymph nodes in your tummy (abdomen). However, a scan isn’t always necessary because these can often be detected on a physical examination.

• #47 Hairy cell leukemia – Diagnosis and treatment – Mayo Clinic

  https://www.mayoclinic.org/diseases-conditions/hairy-cell-leukemia/diagnosis-treatment/drc-20372962

  Enlarged spleen […] To diagnose hairy cell leukemia, your health care provider may recommend: […] Blood tests. You might have a blood test to measure the levels of blood cells in your blood. This test is called a complete blood count (CBC) with differential. […] In hairy cell leukemia, a CBC test may show all levels of these cells are too low. […] Another type of blood test might involve looking at your blood under the microscope. This test can find hairy cell leukemia cells. This test is called a peripheral blood smear. […] Bone marrow biopsy. A bone marrow biopsy is a procedure to remove some of your bone marrow for testing. Your provider will remove a small amount of bone marrow from your hip area. This sample is used to look for hairy cell leukemia cells. […] Lab tests to analyze the leukemia cells. Hairy cell leukemia cells collected from your blood and bone marrow are tested in a lab. These tests look at the changes in the cells’ DNA. This helps your provider understand your prognosis and what treatments are best for you. […] Computerized tomography (CT) scan. A CT scan shows detailed images of the inside of your body. Your provider may order a CT scan to look for swelling in your spleen and your lymph nodes.

• #48 Hairy Cell Leukemia Symptoms & Treatment | Baptist Health

  https://www.baptisthealth.com/care-services/conditions-treatments/hairy-cell-leukemia

  To determine if someone has hairy cell leukemia, we ask about medical history and do a physical exam, particularly looking for an enlarged spleen or lymph nodes. We also use advanced diagnostic procedures and technology to effectively diagnose, inform treatment and carefully monitor the condition. Diagnostic procedures can include: […] Blood tests check for low levels of all three types of blood cells, and specifically for the hairy cells. […] During this test, a local anesthetic is used to numb the area where the sample of bone marrow will be taken, typically on the hip. A small incision is made and a thin, hollow needle goes into the bone to collect a small portion of marrow to examine for hairy cells. […] X-rays and computers are used to create detailed images of the spleen and lymph nodes to look for enlargement.

• #49 Rare Clinical Symptoms in Hairy Cell Leukemia: An Overview

  https://www.mdpi.com/2072-6694/16/17/3054

  The characteristic immunophenotype of classic HCL cells includes the co-expression of CD19, CD20, CD11c, CD25, CD103, CD200, FMC7 and CD123. The unique criterion for the diagnosis of HCL is the co-expression of CD103, CD25 and CD11c. […] Diagnosis and treatment evaluation of bone lesions is based on computed tomography (CT) and positron emission tomography (PET). […] A lung biopsy for histological examination is indicated in patients with pulmonary symptoms if antibiotics and antifungal treatment are not effective. […] In HCL patients, CNS involvement is typically indicated by confusion, aphasia, headache, meningeal syndrome, motor ataxia, dizziness, weakness, confusion, slurred speech, frequent falls, facial droop, fatigue, blurry vision and acute delusional symptoms. […] Diagnosis of leukemia cutis is performed based on the histopathology of skin biopsy and the immunophenotyping of neoplastic cells. Skin biopsy and immunophenotyping must be performed in all patients with suspicion of leukemia cutis. […] Diagnosis is based on peripheral blood (PB) and bone marrow (BM) morphology, flow cytometry, immunophenotyping, immunohistochemistry and molecular studies.

• #50 Hairy Cell Leukemia Differential Diagnoses

  https://emedicine.medscape.com/article/200580-differential

  Hairy cell leukemia (HCL) must be differentiated from other other peripheral small B-cell lymphoid neoplasms, including hairy cell leukemia variant (HCLV), HCL expressing IGHV4-34, and splenic diffuse red pulp lymphoma (SDRPL). While those neoplasms are histologically similar to classic HCL, they have a more aggressive clinical course and are less likely to respond to purine analog therapy. […] Testing for the BRAF V600E mutation allows for a genetics-based differential diagnosis between HCL and HCL-like tumors, as BRAF V600E is absent in other B-cell neoplasms. […] Other problems to be considered in the differential diagnosis of hairy cell leukemia include the following: Primary myelofibrosis, Chronic lymphocytic leukemia, Low-grade lymphoma, Myelosclerosis, Pancytopenia and marrow fibrosis, Prolymphocytic leukemia, Splenic marginal zone lymphoma, Systemic mastocytosis.

• #51 Orphanet: Classic hairy cell leukemia

  https://www.orpha.net/en/disease/detail/58017

  Diagnosis is based on the results of the physical examination, blood tests, and bone marrow biopsy. Abdominal computer tomography may also identify lymphadenopathy. Immunophenotypic evaluations of peripheral blood or bone marrow are essential for establishing the diagnosis. Characteristic immunophenotypic markers include CD11c, CD25, CD103, CD123 positive. BRAF-V600E mutation is also found in most patients. […] Differential diagnoses includes hairy cell leukemia variant, splenic marginal zone lymphoma, and splenic diffuse red pulp B-cell lymphoma.

• #52 International Clinical Cytometry Society

  https://www.cytometry.org/web/q_view.php?id=150&filter=Interpretation%20and%20Clinical%20Application

  How is hairy-cell leukemia diagnosed by flow cytometry? Hairy cell leukemia (HCL) is a relatively rare low-grade B-cell neoplasm, predominantly occurring in middle-aged to elderly patients, especially men. Despite its rarity, it is important to recognize it by flow cytometry because it shares immunophenotypic features with other B-cell neoplasms and it is important to take the necessary steps to distinguish them. This is particularly true because HCL is a relatively indolent disease with a very effective low-intensity treatment. Thus, distinguishing it from other B-cell neoplasms can both reassure the patient and physician and prevent excessive therapy. The basic phenotype of HCL is relatively non-specific. It is positive for CD19 and C20, monotypic for kappa or lambda light chain, and negative for CD5 and CD10. The distinguishing hallmark of HCL is co-expression of CD25 and CD103, which is seen in nearly all cases. Bright CD123 also has been reported as a specific marker of HCL. However, since these markers are often not present in screening panels for B-cell lymphoma, other clinical and phenotypic clues are needed to signal the laboratory that HCL is likely. These additional clues fall into three categories. The first is forward and side scatter. The neoplastic cells of HCL are slightly larger, and thus exhibit higher forward scatter compared to normal small lymphocytes. The increased cytoplasm and membrane irregularities of these cells also increase the side scatter properties. Often, these cells occupy the same position as monocytes on a forward/side scatter plot. The second clue is markedly increased (bright) expression of CD11c, CD22, and CD200 compared with normal B cells. Thus, at least one of these markers should be in routine screening panels to alert to the possibility of HCL in the right immunophenotypic context. The third clue is a relative paucity of monocytes. HCL is one of the few conditions that consistently causes monocytopenia. The presence of one or more of these phenotypic clues, especially in the right clinical and morphologic context, should trigger additional evaluation with a panel containing CD25 and CD103. A number of these markers are important for distinguishing HCL from other entities in the differential diagnosis. Other lymphomas may express CD25 or CD103, but not both. For example, splenic marginal zone and lymphoplasmacytic lymphomas are usually negative for CD103 and hairy cell leukemia-variant is typically negative for CD25. Amongst CD5(-)/CD10(-) B-cell neoplasms, uniformly bright CD200 expression is also fairly unique to HCL. Thus, taken together, this combination of immunophenotypic markers is strong evidence of hairy cell leukemia.

• #53 Hairy Cell Leukemia Treatment (PDQ®): Treatment – Health Professional Information [NCI] | Kaiser Permanente

  https://healthy.kaiserpermanente.org/health-wellness/health-encyclopedia/he.hairy-cell-leukemia-treatment-pdq%C2%AE-treatment-health-professional-information-nci.ncicdr0000062926

  The following tests and procedures may be used to diagnose hairy cell leukemia: […] Although a bone marrow biopsy may be required to enroll in a clinical trial, the hairy cell leukemia diagnosis can usually be made by flow cytometry. […] The BRAF V600E mutation is a hairy cell leukemia defining genetic feature that can be used diagnostically. […] The depth of a complete remission can be evaluated with measurable residual disease (MRD) by using the mutant BRAF gene or immunoglobulin heavy chain gene rearrangement. However, the usefulness of MRD to alter therapeutic choices remains unclear and requires further evaluation.

• #54 Hairy-Cell Leukemia — Onkopedia

  https://www.onkopedia.com/en/onkopedia/guidelines/hairy-cell-leukemia

  Molecular genetic testing for BRAF V600E mutation is recommended to confirm the diagnosis and to differentiate BRAF V600E from other indolent non-Hodgkin lymphomas and HCL. The detection of a BRAF V600E mutation is treatment-guiding for the option of using a BRAF inhibitor. […] Basic and special examinations are also distinguished in the course of the disease, see Table 2. […] In the context of clinical trials, the determination of minimal residual disease (MRD) by immunophenotypic and/or molecular genetic methods is used. It allows earlier assessment of treatment response and may have prognostic relevance. […] Two forms of HCL are distinguished, the so-called classic HCL and the variant. […] The differential diagnosis of cytopenia and splenomegaly is extensive. […] Prognosis has improved markedly since 1980. About 70% of patients with HCL have a normal life expectancy. The response to systemic therapy with purine analogs is crucial. Patients with complete hematologic remission have significantly longer progression-free survival than patients with partial hematologic remission.

• #55 Hairy Cell Leukemia Treatment (PDQ®): Treatment – Health Professional Information [NCI] | Kaiser Permanente

  https://healthy.kaiserpermanente.org/health-wellness/health-encyclopedia/he.hairy-cell-leukemia-treatment-pdq%C2%AE-treatment-health-professional-information-nci.ncicdr0000062926

  The following tests and procedures may be used to diagnose hairy cell leukemia: […] Although a bone marrow biopsy may be required to enroll in a clinical trial, the hairy cell leukemia diagnosis can usually be made by flow cytometry. […] The BRAF V600E mutation is a hairy cell leukemia defining genetic feature that can be used diagnostically. […] The depth of a complete remission can be evaluated with measurable residual disease (MRD) by using the mutant BRAF gene or immunoglobulin heavy chain gene rearrangement. However, the usefulness of MRD to alter therapeutic choices remains unclear and requires further evaluation.

• #56 Hairy-Cell Leukemia — Onkopedia

  https://www.onkopedia.com/en/onkopedia/guidelines/hairy-cell-leukemia

  For examples of microscopic diagnostics, see eLearning Curriculum Hematology (eLCH), https://ehaematology.com/. […] The diagnostic algorithm is divided into basic and special tests, see Table 1. Despite the typical lymphocytopenia, hair cells are detectable in the peripheral blood of most patients, the relative proportion is usually below 10%, often below 1%. Standard in diagnostics is multiparametric immunophenotyping with at least 4 fluorescent dyes and a sensitivity of 1/1,000 cells. […] Standard diagnostic procedure is bone marrow aspiration and biopsy, for characteristic morphology see chapter 2. 1. The detection of a (small) subpopulation of lymphoid cells in peripheral blood with the immunophenotype of hair cells is not sufficient for diagnosis. HCL is one of the hematologic diseases in which punctio sicca frequently occurs, in this case due to fiber formation in the bone marrow.

• #57 Hairy cell leukaemia – Symptoms, diagnosis and treatment | BMJ Best Practice

  https://bestpractice.bmj.com/topics/en-gb/890

  1st investigations to order include FBC with differential, peripheral blood smear, bone marrow trephine biopsy and aspiration (morphology assessment), immunophenotyping (immunohistochemistry or flow cytometry), comprehensive metabolic panel, serum lactate dehydrogenase (LDH), and viral serology for hepatitis B and C. […] Investigations to consider include molecular analysis (for BRAF V600E mutation or IGHV4-34 rearrangement) and CT chest, abdomen, and pelvis.

• #58 2023 Patient Seminar — Hairy Cell Leukemia Foundation

  https://www.hairycellleukemia.org/2023seminar

  Overview: Participants will learn about typical HCL presentation and diagnosis […] We can make the diagnosis easily if we have the right material because the hairy cells express particular proteins, and we can detect those using technology easily now. It’s like having a barcode; your hairy cell has a unique barcode that we can detect. […] Diagnosis of HCL is straightforward with flow cytometry. You have a barcode that can identify and distinguish the cells from normal B-cells and other B-cell malignancies. We use the same technique to look for these proteins in tissue samples from the bone marrow and spleen. You really cannot accurately diagnose hairy cell leukemia without a bone marrow. It is essential because mistakes are made when the bone marrow hasn’t been examined. […] So, you have to confirm the diagnosis with a bone marrow, which you can use to accurately assess the infiltration and the BRAF.

• #59 Understanding Hairy Cell Leukemia — Hairy Cell Leukemia Foundation

  https://www.hairycellleukemia.org/hairy-cell-leukemia

  The peripheral blood smear will often show a reduction or absence of a type of white blood cells called monocytes, and may document the appearance of cells with a pale cytoplasm with a hairy rim. […] Immunophenotyping is a test that helps identify the hairy cells with the use of markers (so called clusters of differentiation or CD) by monoclonal antibodies, each of which has a number or a name and will be expressed on all the malignant cells. […] A bone marrow biopsy is performed by using a needle to take a sample of bone near the rear area of the hip. […] An accurate diagnosis is necessary to determine the correct treatment for each patient. It may be helpful to seek consultation at a Center of Excellence.

• #60 What Is Hairy Cell Leukemia? Treatment, Symptoms, and Causes

  https://www.everydayhealth.com/hairy-cell-leukemia/

  Hairy cell leukemia (HCL) is a slow-growing blood cancer. It is rare, accounting for only 1 to 2 percent of all cases of adult leukemia. […] A diagnosis of hairy cell leukemia involves a number of tests: […] A firm diagnosis of hairy cell leukemia requires another type of evaluation called immunophenotyping. […] Your doctor may also use a genetic test on the cancerous cells to see if they carry the BRAF mutation. This information can help them target your treatment. […] Hairy cell leukemia is considered a chronic condition, meaning it is incurable. […] But the good news is that it is highly treatable. […] Finding a doctor who has specialized knowledge of this leukemia can make a significant difference in outcome. […] Treatment for hairy cell leukemia can take a number of forms.

• #61 About Hairy Cell Leukemia (HCL) | Memorial Sloan Kettering Cancer Center

  https://www.mskcc.org/cancer-care/types/leukemias/types/about-hairy-cell-leukemia-hcl

  Hairy cell leukemia (HCL) is a rare chronic leukemia in adults. Around 1,000 people in the United States develop HCL each year, according to the World Health Organization. The average age at diagnosis is 52. HCL is more common in men than in women. There is no clear evidence that HCL runs in families or is caused by specific environmental factors. […] Doctors do a variety of tests to diagnose HCL. These include blood tests and bone marrow tests. Some of these tests look for specific features of the leukemia cells to confirm the diagnosis and determine how advanced the HCL is. Occasionally, imaging tests (a CT scan or an ultrasound) may be needed to study the spleen. Because it is rare, HCL is not always easy to diagnose. Sometimes it takes the experience of someone whos skilled in identifying hairy cell leukemia to arrive at an accurate diagnosis. […] Specialized testing of the genetics of the leukemia cells may be helpful in diagnosis and treatment. For example, mutations in a gene called BRAF are found in the leukemia cells of most people with HCL. The results of these diagnostic tests help doctors create a personalized treatment plan.

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