BRAFV600E mutation in hairy cell leukemia: A single-center experience

Hairy Cell Leukemia: Morphological and Immunophenotypic Characteristics of Seven Cases and Cyclin D1 Expression

Aberrant immunophenotypic expression in hairy cell leukemia (HCL), both at medullary and extramedullary sites, is not uncommonly reported in literature. Cyclin D1 positivity in HCL may mimic mantle cell lymphoma (MCL) morphologically, especially in the presence of aberrant CD5 immunopositivity, requiring BRAFV600E mutation and/or CCND1 gene testing for confirmation. Here, we describe seven cases of HCL with clinicomorphological and immunophenotypic characteristics with an emphasis on cyclin D1 expression using immunohistochemistry (IHC) with a brief comprehensive literature review. We suggest that cyclin D1 positive HCL may be a distinct subtype which requires further immunophenotypic and molecular characterization for accurate diagnosis and planning of definitive therapy.

Severe Systemic Rash in the Treatment of Hairy Cell Leukemia with Cladribine: Case Report and Literature Review

A 49-year-old male patient who had been diagnosed with variable hairy cell leukemia (HCL-V) was treated with interferon for half a year but exert no obvious effect. After two courses of chemotherapy with cladribine, he achieved remission, and splenomegaly significantly improved (the length in craniocaudal dimension decreased from 15.8cm to 11.8cm). Four years later, the patient got disease relapse and was recommended for another cycle of cladribine (6mg for 7 days). On the last day of cladribine, the patient developed fever with needle-like red rashes on the face, limbs, and trunk. At the very beginning, the rash was lighter in color, sparsely distributed, and without obvious itching. Three days later, the rash gradually darkened, expanded and merged, with itching. With the application of high dose gamma globulin and corticosteroids (prednisolone combined with dexamethasone), the rash finally faded, and the patient was discharged. Rash caused by cladribine is not uncommon, such serious and widespread drug-induced rash is rare, and there are few reports. This article reviewed relevant studies and treatments.