Hairy Cell Leukemia-variant (HCL-v)

Hairy cell leukemia variant (HCL-v) is rare and can be a morphological challenge, with characteristics intermediate between hairy cells and prolymphocytes. The cells are large with basophilic cytoplasm with small projections and relatively prominent nucleoli, although they can be absent or inconspicuous.
Immunophenotypic analysis by multi-parameter flow cytometry (FCM) is essential in establishing the diagnosis and the cells are typically positive for CD20, CD22, CD11c, CD103 and negative for CD25 and CD123. No BRAF mutation present.