Variant hairy cell leukemia (HCL-V) is defined as a rare and indolent form of small, mature B-cell leukemia and is characterized by splenomegaly, an elevated white blood cell count (WBC), and hypercellular bone marrow . HCL-V is more aggressive and therapy resistant than classical HLC (C-HLC) (see this term).
Summary
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- 1 Synonyms
- 2 Prevalence
- 3 Inheritance
- 4 Age of onset or onset
- 5 Epidemiology
- 6 Clinical description
- 7 Diagnostic methods
- 1 Differential diagnosis
- 8 Management and treatment
- 9 Forecast
- 10 Sources
Synonyms
- HCL-v
- Variant of leukemic reticuloendotheliosis
- Prolymphocytic variant of LCH
- Prolymphocytic variant of hairy cell leukemia
Prevalence
- Unknown
Heritage
- Multigenic / multifactorial
Age of onset or onset
- Adulthood
epidemiology
HCL-V represents about 10-20% of patients with LCH and 0.4% of all lymphoid neoplasms . There are approximately 60-75 new patients diagnosed with HCL-V each year in the United States .
Clinical description
HCL-V frequently affects the older population (mean age: 71 years) without a significant gender predominance (male / female: 1.6). The most frequent manifestations at the beginning are abdominal discomfort or bloating, normally related to splenomegaly, hepatomegaly and manifestations derived from cytopenias such as anemia., bleeding and / or infections. Autoimmune manifestations, such as Coombs-positive hemolytic anemia, are rare. A disease similar to HCL-V has been described in Japan, and has been termed Japanese variant HCL (HCL-Jv; see this term). Etiology The etiology is unknown but there is no evidence of an association due to exposure to carcinogens, radiation, or viral infections. Loss of the P53 allele due to monosomy or monoallelic deletion has been related. Unlike HCL, HCL-V individuals are usually negative for the BRAF-V600E mutation. Furthermore, the most common VH gene found in HCL-V (IGHVH4-34 (14q32.33)) has a very high homology with its germline sequence and is associated with symptoms characteristic of HCL-V, such as older age, higher leukocytosis, poor response to therapy, and less survival. HCL-V is not considered to be biologically related to HCL.
Diagnostic methods
The diagnosis is suspected after a physical examination, a spleen and bone marrow biopsy , and a scan (CAT), as well as by laboratory analysis showing an elevated white blood cell count (> 10 × 109 / l). Morphologically, HCL-V cells are similar to HCL-C but with an increased nucleus-cytoplasm ratio and without ribosome-lamellar complexes. HCL-V cells show no reactivity to tartrate-resistant acid phosphatase (TRAP). The diagnosis of HCL-V is confirmed by immunophenotyping by flow cytometry (HCL-V cells are always CD25 negative and CD11C positive) and chronic lymphocytic leukemia (CLL) score . The LLC score is based on the immunophenotypic analysis of five membrane markers(CD5, CD22, CD23, FMC7, SmIg). The score obtained is the result of the expression level of each marker. The HCL-V will score between 0 and 1.
Differential diagnosis
Differential diagnosis includes lymphoma Splenic by lymphocytes villous (SLVL), splenic lymphoma diffuse the pulp red (SRPL), HCL-C, lymphoma cell mantle, leukemia Prolymphocytic of B (B-PLL) and HCL-Jv cells.
Management and treatment
There is no effective treatment for V-HCL. In two thirds of patients, splenectomy produces a partial remission. Very rarely, patients can achieve complete remission after three or four cycles of cladribine (European Marketing Authorization 2009 , orphan designation). Combination treatment of purine analogues (cladribine or pentostatin) with rituximab or anti-CD22, BL22 immunotoxin with rituximab may benefit some patients.
Forecast
HCL-V is an aggressive disease with a chronic clinical course. Median survival is nine years, with only 15% survival at 15 years and poor response to purine analogues. However, complete remission can be achieved with rituximab and the anti-CD22 immunotoxin, BL22.
