Hairy cell leukaemia with low CD103 expression: A rare but important diagnostic pitfall.

On flow cytometry, HCL cells express brightly mature B-lymphoid cell antigens as CD19, CD20, CD22, CD200, are typically positive for CD11c, CD103, CD123 and CD25, while are usually negative or dim for CD5, CD23, CD10, CD79b and CD27. Three cases (3/71, 4%) - despite expressing CD25, CD11c, and CD200 on all clonal cells (which were 15%, 22% and 37% of total leukocytes, respectively) - had CD103 expressed only on a fraction of leukaemic cells (40%, 27%, and 10.8%, corresponding to 5%, 6% and 4% of total leukocytes) (Figure 1A). Keywords: CD103; flow cytometry; hairy cell leukaemia EN CD103 flow cytometry hairy cell leukaemia e28 e31 4 07/18/22 20220715 NES 220715 Classical hairy cell leukaemia (HCLc) is an uncommon mature B-cell lymphoproliferative neoplasm (MBCLN) comprising about 2% of lymphoid leukaemias. [Extracted from the article]