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==Overview==
==Overview==
Hairy cell leukemia arises from  [[B cell]]s, that are normally involved in the process of human [[immunoglobulin]]s production.<ref name="m">Magrath I. The Lymphoid Neoplasms 3ed. CRC Press; 2010.</ref> However, the exact B cell maturation stage involved in the development of hairy cell leukemia is still unclear.<ref name="found">What is Hairy Cell Leukemia? Hairy Cell Leukemia Foundation (2015) https://www.hairycellleukemia.org/about-hcl/what-is-hairy-cell-leukemia/ Accessed on October, 19 2015</ref> The most common gene involved in the pathogenesis of hairy cell leukemia is BRAF V600E mutation.<ref name="wiki"> Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accessed on Ocotber, 19 2015</ref> On microscopic histopathological analysis, characteristic findings of hairy cell leukemia include small cells with "fried egg"-like appearance, well-demarcated thread-like cytoplasmic extensions, and a clear cytoplasm.<ref name="patho">Hairy cell leukemia. Libre Pathology (2015) http://librepathology.org/wiki/index.php/Small_cell_lymphomas#Hairy_cell_leukemia Accessed on October, 8 2015</ref> Hairy cell leukemia is found to approximately comprise 2% of all leukemias in the United States.<ref name="wiki">Hairy Cell Leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accesed on October, 20 2015</ref> The incidence of hairy cell leukemia is approximately 3.2 per 1,000,000 individuals in the United States. The incidence of hairy cell leukemia increases with age; the median age at diagnosis is 58 years. Males are more commonly affected with hairy cell leukemia than females. The male to female ratio is approximately 4 to 1.<ref name="found"> Epidemiology. HAIRY CELL LEUKEMIA FOUNDATION. (2015) https://www.hairycellleukemia.org/professionals/epidemiology/ Accessed on October, 21 2015</ref> Studies have proposed a number of risk factors for the development of hairy cell leukmeia such as certain chemicals exposure, radiation exposure, and sawdust exposure.<ref name="may">Hairy cell leukemia. MAYO CLINIC (2015) http://www.mayoclinic.org/diseases-conditions/hairy-cell-leukemia/basics/risk-factors/con-20026432 Accessed on October, 20 2015</ref> Symptoms of hairy cell leukemia include [[fever]], night sweats, and [[weight loss]].<ref name="wiki">Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Signs_and_symptoms Accessed on October, 28 2015</ref><ref name="gov">Hairy cell leukemia. National Cancer Institute (2015) http://www.cancer.gov/types/leukemia/hp/hairy-cell-treatment-pdq Accessed on October, 28 2015</ref> Physical examination of patients with hairy cell leukemia is usually remarkable for [[pallor]], [[petechiae]], and [[splenomegaly]].<ref name="found"> Epidemiology. HAIRY CELL LEUKEMIA FOUNDATION. (2015) https://www.hairycellleukemia.org/professionals/epidemiology/ Accessed on October, 28 2015</ref> Laboratory findings consistent with the diagnosis of hairy cell leukemia include abnormal complete blood count, immunohistochemistry, and flow cytometry. The presence of hairy cells with thread-like [[cytoplasmic]] extensions on blood smear is a key diagnostic feature among patients with hairy cell leukemia.<ref name="pub">{{cite journal |vauthors=Somasundaram V, Purohit A, Aggarwal M, Manivannan P, Mishra P, Seth T, Tyagi S, Mahapatra M, Pati HP, Saxena R |title=Hairy cell leukemia: A decade long experience of North Indian Hematology Center |journal=Indian J Med Paediatr Oncol |volume=35 |issue=4 |pages=271–5 |year=2014 |pmid=25538404 |pmc=4264273 |doi=10.4103/0971-5851.144988 |url=}}</ref><ref name="patho">Small cell lymphoma. Libre Pathology (2015) http://librepathology.org/wiki/index.php/Small_cell_lymphomas#Hairy_cell_leukemia Accessed on October, 8 2015</ref> There are no '''curative''' treatments for hairy cell leukemia. The mainstay of therapy for hairy cell leukemia patients is chemotherapy. Pharmacological agents used for the treatment of hairy cell leukemia patients include [[cladribine]], [[pentostatin]], [[rituximab]], and [[vemurafenib]].<ref name="wiki"> Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accessed on Ocotber, 25 2015</ref><ref name="NCCN">NCCN Guidelines Version 2.2015 CLL/SLL. National Comprehensive Cancer Network. (2015) http://www.nccn.org/professionals/physician_gls/PDF/nhl.pdf Accessed on October, 25 2015</ref><ref name="pub4">National Cancer Institute: PDQ® Hairy Cell Leukemia Treatment. Bethesda, MD: National Cancer Institute. http://www.cancer.gov/types/leukemia/hp/hairy-cell-treatment-pdq. Accessed October, 25 2015</ref><ref name="pub7">{{cite journal |vauthors=Cornet E, Damaj G, Troussard X |title=New insights in the management of patients with hairy cell leukemia |journal=Curr Opin Oncol |volume=27 |issue=5 |pages=371–6 |year=2015 |pmid=26154707 |doi=10.1097/CCO.0000000000000214 |url=}}</ref>
Hairy cell leukemia arises from  [[B cell]]s, that are normally involved in the process of human [[immunoglobulin]]s production. However, the exact B cell maturation stage involved in the development of hairy cell leukemia is still unclear. The most common gene involved in the pathogenesis of hairy cell leukemia is BRAF V600E mutation. On microscopic histopathological analysis, characteristic findings of hairy cell leukemia include small cells with "fried egg"-like appearance, well-demarcated thread-like cytoplasmic extensions, and a clear cytoplasm. Hairy cell leukemia is found to approximately comprise 2% of all leukemias in the United States. The incidence of hairy cell leukemia is approximately 3.2 per 1,000,000 individuals in the United States. The incidence of hairy cell leukemia increases with age; the median age at diagnosis is 58 years. Males are more commonly affected with hairy cell leukemia than females. The male to female ratio is approximately 4 to 1. Studies have proposed a number of risk factors for the development of hairy cell leukmeia such as certain chemicals exposure, radiation exposure, and sawdust exposure. Symptoms of hairy cell leukemia include [[fever]], night sweats, and [[weight loss]].  Physical examination of patients with hairy cell leukemia is usually remarkable for [[pallor]], [[petechiae]], and [[splenomegaly]]. Laboratory findings consistent with the diagnosis of hairy cell leukemia include abnormal complete blood count, immunohistochemistry, and flow cytometry. The presence of hairy cells with thread-like [[cytoplasmic]] extensions on blood smear is a key diagnostic feature among patients with hairy cell leukemia. There are no '''curative''' treatments for hairy cell leukemia. The mainstay of therapy for hairy cell leukemia patients is chemotherapy. Pharmacological agents used for the treatment of hairy cell leukemia patients include [[cladribine]], [[pentostatin]], [[rituximab]], and [[vemurafenib]].


==Historical Perspective==
==Historical Perspective==
The term hairy cell leukemia was first used to describe the malignancy by Dr. R. Schrek and Dr. W. J. Donnelly, in 1966.<ref name="pmid18283787">{{cite journal| author=Fanta PT, Saven A| title=Hairy cell leukemia. | journal=Cancer Treat Res | year= 2008 | volume= 142 | issue=  | pages= 193-209 | pmid=18283787 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=18283787  }} </ref>
The term hairy cell leukemia was first used to describe the malignancy by Dr. R. Schrek and Dr. W. J. Donnelly, in 1966.  
==Classification==
==Classification==
Hairy cell leukemia may be classified  into two subtypes which include hairy cell leukemia (classic) and hairy cell leukemia variant.<ref name="wiki">Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Classification Accessed on October, 17 2015</ref>
Hairy cell leukemia may be classified  into two subtypes which include hairy cell leukemia (classic) and hairy cell leukemia variant.


==Pathogenesis==
==Pathogenesis==
Hairy cell leukemia arises from  [[B cell]]s, that are normally involved in the process of human [[immunoglobulin]]s production.<ref name="m">Magrath I. The Lymphoid Neoplasms 3ed. CRC Press; 2010.</ref> However, the exact B cell maturation stage involved in the development of hairy cell leukemia is still unclear.<ref name="found">What is Hairy Cell Leukemia? Hairy Cell Leukemia Foundation (2015) https://www.hairycellleukemia.org/about-hcl/what-is-hairy-cell-leukemia/ Accessed on October, 19 2015</ref> The most common gene involved in the pathogenesis of hairy cell leukemia is BRAF V600E mutation.<ref name="wiki"> Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accessed on Ocotber, 19 2015</ref> On microscopic histopathological analysis, characteristic findings of hairy cell leukemia include small cells with "fried egg"-like appearance, well-demarcated thread-like cytoplasmic extensions, and a clear cytoplasm.<ref name="patho">Hairy cell leukemia. Libre Pathology (2015) http://librepathology.org/wiki/index.php/Small_cell_lymphomas#Hairy_cell_leukemia Accessed on October, 8 2015</ref>
Hairy cell leukemia arises from  [[B cell]]s, that are normally involved in the process of human [[immunoglobulin]]s production. However, the exact B cell maturation stage involved in the development of hairy cell leukemia is still unclear. The most common gene involved in the pathogenesis of hairy cell leukemia is BRAF V600E mutation. On microscopic histopathological analysis, characteristic findings of hairy cell leukemia include small cells with "fried egg"-like appearance, well-demarcated thread-like cytoplasmic extensions, and a clear cytoplasm.


==Causes==
==Causes==
There are no established direct causes for hairy cell leukemia. Common genetic mutations involved in the development of hairy cell leukemia can be found [[Hairy cell leukemia pathophysiology|'''here''']].<ref name="wiki"> Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accessed on Ocotber, 19 2015</ref><ref name="pmid16723990">{{cite journal| author=Tiacci E, Liso A, Piris M, Falini B| title=Evolving concepts in the pathogenesis of hairy-cell leukaemia. | journal=Nat Rev Cancer | year= 2006 | volume= 6 | issue= 6 | pages= 437-48 | pmid=16723990 | doi=10.1038/nrc1888 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=16723990  }} </ref>
There are no established direct causes for hairy cell leukemia. Common genetic mutations involved in the development of hairy cell leukemia.
==Epidemiology and Demographics==
==Epidemiology and Demographics==
Hairy cell leukemia is found to approximately comprise 2% of all leukemias in the United States.<ref name="wiki">Hairy Cell Leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accesed on October, 20 2015</ref> The incidence of hairy cell leukemia is approximately 3.2 per 1,000,000 individuals in the United States. The incidence of hairy cell leukemia increases with age; the median age at diagnosis is 58 years. Males are more commonly affected with hairy cell leukemia than females. The male to female ratio is approximately 4 to 1.<ref name="found"> Epidemiology. HAIRY CELL LEUKEMIA FOUNDATION. (2015) https://www.hairycellleukemia.org/professionals/epidemiology/ Accessed on October, 21 2015</ref>
Hairy cell leukemia is found to approximately comprise 2% of all leukemias in the United States. The incidence of hairy cell leukemia is approximately 3.2 per 1,000,000 individuals in the United States. The incidence of hairy cell leukemia increases with age; the median age at diagnosis is 58 years. Males are more commonly affected with hairy cell leukemia than females. The male to female ratio is approximately 4 to 1.
==Risk Factors==
==Risk Factors==
Studies have proposed a number of risk factors for the development of hairy cell leukmeia such as certain chemicals exposure, radiation exposure, and sawdust exposure.<ref name="may">Hairy cell leukemia. MAYO CLINIC (2015) http://www.mayoclinic.org/diseases-conditions/hairy-cell-leukemia/basics/risk-factors/con-20026432 Accessed on October, 20 2015</ref>
Studies have proposed a number of risk factors for the development of hairy cell leukemia such as certain chemicals exposure, radiation exposure, and sawdust exposure.
==Screening==
==Screening==
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for hairy cell leukemia.<ref name="US">Recommendations. US preventive services task force (2015) http://www.uspreventiveservicestaskforce.org/BrowseRec/Search?s=Hairy+cell+leukemia+ Accessed on October, 12 2015</ref>
According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for hairy cell leukemia.
==Natural History==
==Natural History==
Most patients with hairy cell leukemia are asymptomatic at the time of diagnosis. If left untreated, most of the patients with hairy cell leukemia will gradually develop [[anemia]], recurrent infections, and recurrent [[bleeding]]. The complications of hairy cell leukemia are mainly due to [[bone marrow failure]].<ref name="found">What is Hairy Cell Leukemia? Hairy Cell Leukemia Foundation (2015) https://www.hairycellleukemia.org/about-hcl/what-is-hairy-cell-leukemia/ Accessed on October, 19 2015</ref><ref name="wiki">Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Signs_and_symptoms Accessed on October, 28 2015</ref><ref name="gov">Hairy cell leukemia. National Cancer Institute (2015) http://www.cancer.gov/types/leukemia/hp/hairy-cell-treatment-pdq Accessed on October, 28 2015</ref>
Most patients with hairy cell leukemia are asymptomatic at the time of diagnosis. If left untreated, most of the patients with hairy cell leukemia will gradually develop [[anemia]], recurrent infections, and recurrent [[bleeding]]. The complications of hairy cell leukemia are mainly due to [[bone marrow failure]].


==Diagnosis==
==Diagnosis==
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There is no established system for the staging of hairy cell leukemia.  
There is no established system for the staging of hairy cell leukemia.  
===History and Symptoms===
===History and Symptoms===
Symptoms of hairy cell leukemia include [[fever]], night sweats, and [[weight loss]].<ref name="wiki">Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Signs_and_symptoms Accessed on October, 28 2015</ref><ref name="gov">Hairy cell leukemia. National Cancer Institute (2015) http://www.cancer.gov/types/leukemia/hp/hairy-cell-treatment-pdq Accessed on October, 28 2015</ref>
Symptoms of hairy cell leukemia include [[fever]], night sweats, and [[weight loss]].
===Physical Examination===
===Physical Examination===
Physical examination of patients with hairy cell leukemia is usually remarkable for [[pallor]], [[petechiae]], and [[splenomegaly]].<ref name="found"> Epidemiology. HAIRY CELL LEUKEMIA FOUNDATION. (2015) https://www.hairycellleukemia.org/professionals/epidemiology/ Accessed on October, 28 2015</ref>
Physical examination of patients with hairy cell leukemia is usually remarkable for [[pallor]], [[petechiae]], and [[splenomegaly]].


===Laboratory Findings===
===Laboratory Findings===
Laboratory findings consistent with the diagnosis of hairy cell leukemia include abnormal complete blood count, immunohistochemistry, and flow cytometry. The presence of hairy cells with thread-like [[cytoplasmic]] extensions on blood smear is a key diagnostic feature among patients with hairy cell leukemia.<ref name="patho">Small cell lymphoma. Libre Pathology (2015) http://librepathology.org/wiki/index.php/Small_cell_lymphomas#Hairy_cell_leukemia Accessed on October, 8 2015</ref><ref name="pub">{{cite journal |vauthors=Somasundaram V, Purohit A, Aggarwal M, Manivannan P, Mishra P, Seth T, Tyagi S, Mahapatra M, Pati HP, Saxena R |title=Hairy cell leukemia: A decade long experience of North Indian Hematology Center |journal=Indian J Med Paediatr Oncol |volume=35 |issue=4 |pages=271–5 |year=2014 |pmid=25538404 |pmc=4264273 |doi=10.4103/0971-5851.144988 |url=}}</ref>
Laboratory findings consistent with the diagnosis of hairy cell leukemia include abnormal complete blood count, immunohistochemistry, and flow cytometry. The presence of hairy cells with thread-like [[cytoplasmic]] extensions on blood smear is a key diagnostic feature among patients with hairy cell leukemia.


===CT Scan===
===CT Scan===
Abdominal CT scan may be helpful in the diagnosis of hairy cell leukemia. The presence of [[splenomegaly]] on CT scan is suggestive of hairy cell leukemia.<ref name="mayo">Diseases and conditions Hairy cell leukemia. MAYO CLINIC (2015) http://www.mayoclinic.org/diseases-conditions/hairy-cell-leukemia/basics/tests-diagnosis/con-20026432 Accessed on October, 28 2015</ref>
Abdominal CT scan may be helpful in the diagnosis of hairy cell leukemia. The presence of [[splenomegaly]] on CT scan is suggestive of hairy cell leukemia.


===MRI===
===MRI===
MRI of the femur may be helpful in the diagnosis of hairy cell leukemia. Diffuse hyperintense lesions on T2-weighted MRI image is suggestive of bone marrow infiltration by malignant leukemic cells.<ref name="pub1">{{cite journal |vauthors=Silingardi V, Davolio-Marani S, Federico M, Piccinini L, Frassoldati A, Sarti M, Burani A, Canossi G |title=Bone marrow infiltration in hairy cell leukemia after interferon therapy detected by magnetic resonance imaging |journal=Eur J Cancer Clin Oncol |volume=25 |issue=2 |pages=209–13 |year=1989 |pmid=2702977 |doi= |url=}}</ref><ref name="pub2">{{cite journal |vauthors=Thompson JA, Shields AF, Porter BA, Olson DO, Rubin E, Kidd P, Fefer A |title=Magnetic resonance imaging of bone marrow in hairy cell leukemia: correlation with clinical response to alpha-interferon |journal=Leukemia |volume=1 |issue=4 |pages=315–6 |year=1987 |pmid=3669752 |doi= |url=}}</ref><ref name="pub3">{{cite journal |vauthors=Gray MT, Rutherford MN, Bonin DM, Patterson B, Lopez PG |title=Hairy-cell leukemia presenting as lytic bone lesions |journal=J. Clin. Oncol. |volume=31 |issue=25 |pages=e410–2 |year=2013 |pmid=23797001 |doi=10.1200/JCO.2012.47.5301 |url=}}</ref>
MRI of the femur may be helpful in the diagnosis of hairy cell leukemia. Diffuse hyperintense lesions on T2-weighted MRI image is suggestive of bone marrow infiltration by malignant leukemic cells.


==Medical Therapy==
==Medical Therapy==
There are no '''curative''' treatments for hairy cell leukemia. The mainstay of therapy for hairy cell leukemia patients is chemotherapy. Pharmacological agents used for the treatment of hairy cell leukemia patients include [[cladribine]], [[pentostatin]], [[rituximab]], and [[vemurafenib]].<ref name="wiki"> Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accessed on Ocotber, 25 2015</ref><ref name="NCCN">NCCN Guidelines Version 2.2015 CLL/SLL. National Comprehensive Cancer Network. (2015) http://www.nccn.org/professionals/physician_gls/PDF/nhl.pdf Accessed on October, 25 2015</ref><ref name="pub4">National Cancer Institute: PDQ® Hairy Cell Leukemia Treatment. Bethesda, MD: National Cancer Institute. http://www.cancer.gov/types/leukemia/hp/hairy-cell-treatment-pdq. Accessed October, 25 2015</ref><ref name="pub7">{{cite journal |vauthors=Cornet E, Damaj G, Troussard X |title=New insights in the management of patients with hairy cell leukemia |journal=Curr Opin Oncol |volume=27 |issue=5 |pages=371–6 |year=2015 |pmid=26154707 |doi=10.1097/CCO.0000000000000214 |url=}}</ref>
There are no '''curative''' treatments for hairy cell leukemia. The mainstay of therapy for hairy cell leukemia patients is chemotherapy. Pharmacological agents used for the treatment of hairy cell leukemia patients include [[cladribine]], [[pentostatin]], [[rituximab]], and [[vemurafenib]].


==Surgery==
==Surgery==
The predominant therapy for hairy cell leukemia is chemotherapy. Surgical management, such as [[splenectomy]], may be required in certain cases.<ref name="wiki"> Hairy cell leukemia. Wikipedia (2015) https://en.wikipedia.org/wiki/Hairy_cell_leukemia#Pathophysiology Accessed on Ocotber, 25 2015</ref>
The predominant therapy for hairy cell leukemia is chemotherapy. Surgical management, such as [[splenectomy]], may be required in certain cases.


==References==
==References==

Revision as of 17:18, 6 December 2018

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Haytham Allaham, M.D. [2]

Overview

Hairy cell leukemia arises from B cells, that are normally involved in the process of human immunoglobulins production. However, the exact B cell maturation stage involved in the development of hairy cell leukemia is still unclear. The most common gene involved in the pathogenesis of hairy cell leukemia is BRAF V600E mutation. On microscopic histopathological analysis, characteristic findings of hairy cell leukemia include small cells with "fried egg"-like appearance, well-demarcated thread-like cytoplasmic extensions, and a clear cytoplasm. Hairy cell leukemia is found to approximately comprise 2% of all leukemias in the United States. The incidence of hairy cell leukemia is approximately 3.2 per 1,000,000 individuals in the United States. The incidence of hairy cell leukemia increases with age; the median age at diagnosis is 58 years. Males are more commonly affected with hairy cell leukemia than females. The male to female ratio is approximately 4 to 1. Studies have proposed a number of risk factors for the development of hairy cell leukmeia such as certain chemicals exposure, radiation exposure, and sawdust exposure. Symptoms of hairy cell leukemia include fever, night sweats, and weight loss. Physical examination of patients with hairy cell leukemia is usually remarkable for pallor, petechiae, and splenomegaly. Laboratory findings consistent with the diagnosis of hairy cell leukemia include abnormal complete blood count, immunohistochemistry, and flow cytometry. The presence of hairy cells with thread-like cytoplasmic extensions on blood smear is a key diagnostic feature among patients with hairy cell leukemia. There are no curative treatments for hairy cell leukemia. The mainstay of therapy for hairy cell leukemia patients is chemotherapy. Pharmacological agents used for the treatment of hairy cell leukemia patients include cladribine, pentostatin, rituximab, and vemurafenib.

Historical Perspective

The term hairy cell leukemia was first used to describe the malignancy by Dr. R. Schrek and Dr. W. J. Donnelly, in 1966.

Classification

Hairy cell leukemia may be classified into two subtypes which include hairy cell leukemia (classic) and hairy cell leukemia variant.

Pathogenesis

Hairy cell leukemia arises from B cells, that are normally involved in the process of human immunoglobulins production. However, the exact B cell maturation stage involved in the development of hairy cell leukemia is still unclear. The most common gene involved in the pathogenesis of hairy cell leukemia is BRAF V600E mutation. On microscopic histopathological analysis, characteristic findings of hairy cell leukemia include small cells with "fried egg"-like appearance, well-demarcated thread-like cytoplasmic extensions, and a clear cytoplasm.

Causes

There are no established direct causes for hairy cell leukemia. Common genetic mutations involved in the development of hairy cell leukemia.

Epidemiology and Demographics

Hairy cell leukemia is found to approximately comprise 2% of all leukemias in the United States. The incidence of hairy cell leukemia is approximately 3.2 per 1,000,000 individuals in the United States. The incidence of hairy cell leukemia increases with age; the median age at diagnosis is 58 years. Males are more commonly affected with hairy cell leukemia than females. The male to female ratio is approximately 4 to 1.

Risk Factors

Studies have proposed a number of risk factors for the development of hairy cell leukemia such as certain chemicals exposure, radiation exposure, and sawdust exposure.

Screening

According to the the U.S. Preventive Service Task Force (USPSTF), there is insufficient evidence to recommend routine screening for hairy cell leukemia.

Natural History

Most patients with hairy cell leukemia are asymptomatic at the time of diagnosis. If left untreated, most of the patients with hairy cell leukemia will gradually develop anemia, recurrent infections, and recurrent bleeding. The complications of hairy cell leukemia are mainly due to bone marrow failure.

Diagnosis

Staging

There is no established system for the staging of hairy cell leukemia.

History and Symptoms

Symptoms of hairy cell leukemia include fever, night sweats, and weight loss.

Physical Examination

Physical examination of patients with hairy cell leukemia is usually remarkable for pallor, petechiae, and splenomegaly.

Laboratory Findings

Laboratory findings consistent with the diagnosis of hairy cell leukemia include abnormal complete blood count, immunohistochemistry, and flow cytometry. The presence of hairy cells with thread-like cytoplasmic extensions on blood smear is a key diagnostic feature among patients with hairy cell leukemia.

CT Scan

Abdominal CT scan may be helpful in the diagnosis of hairy cell leukemia. The presence of splenomegaly on CT scan is suggestive of hairy cell leukemia.

MRI

MRI of the femur may be helpful in the diagnosis of hairy cell leukemia. Diffuse hyperintense lesions on T2-weighted MRI image is suggestive of bone marrow infiltration by malignant leukemic cells.

Medical Therapy

There are no curative treatments for hairy cell leukemia. The mainstay of therapy for hairy cell leukemia patients is chemotherapy. Pharmacological agents used for the treatment of hairy cell leukemia patients include cladribine, pentostatin, rituximab, and vemurafenib.

Surgery

The predominant therapy for hairy cell leukemia is chemotherapy. Surgical management, such as splenectomy, may be required in certain cases.

References


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