ABSTRACT
Introduction
Hairy cell leukemia-variant (HCL-V) is a rare B-cell neoplasm arising or homing primarily in the spleen. It has been considered in the WHO classification of Hemopoietic and Lymphoid Tumors as a provisional entity since 2008 and included under the umbrella of unclassifiable splenomegalic B-cell leukemia/lymphomas. The diagnosis is a challenge to hematopathologists and management of these patients by the clinicians is difficult due to the lack of diagnostic and therapeutic guidelines and prospective studies.
Areas covered
This manuscript is a comprehensive review of the clinical features, pathology, immunophenotypic profile, genomic alterations and therapeutic options of HCL-V. Diagnostic and therapeutic dilemmas are extensively outlined considering the information derived from a literature search covering from 1980 to 2019. Integration of all the data is needed and recommended for establishing the diagnosis of this leukemia.
Expert opinion
More extensive information of genomic aberrations underlying the pathogenesis of the disease would be a solid stone for the diagnosis. To this end, a collaborative work among scientists and pathologists from different centers is required and expected. In turn, this might have a relevant clinical translation by allowing to identify putative targets for therapy and to improve the outlook of these patients.
Article highlights
HCL-V is included as a provisional entity in the WHO classification under the umbrella of unclassifiable splenic B cell leukemia/lymphoma
It is considered to be biologically unrelated to typical HCL
It has overlapping histological features with splenic diffuse red pulp lymphoma (SDRPL) but different cytology and outcome
The diagnosis is a challenge to hematopathologists. This should be made on a constellation of features that includes cytology, flow cytometry, bone marrow histology and if available splenic histology
Mutations of TP53 are frequent. MAP2K1 gene mutations have been documented with variable frequency whilst mutations on the BRAF gene have not been reported
Age, anemia and TP53 mutations seem to be adverse prognostic factors for survival
Unlike typical HCL, responses to single agent purine analog are not satisfactory. The best available option is chemoimmunotherapy
The clinical course is chronic and median survivals range from 7 to 9 years
Disclosure
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
Reviewer disclosures
Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.