Case: A 63-year-old woman being followed for splenomegaly presented with lymphocytosis (hemoglobin, 14 g/dL; neutrophils, 2.5 × 109/L; lymphocytes, 8.5 × 109/L; monocytes, 0.7 × 109/L; platelets, 200 × 109/L). A blood smear showed 40% medium-sized lymphocytes with abundant cytoplasm with circumferential projections, similar to those of classic hairy cells. The nucleus had condensed chromatin with a conspicuous nucleolus (panels A-F). Flow cytometry revealed 45% clonal B lymphocytes that expressed CD19/CD20/CD22/CD103/CD11c and a lack of CD5/CD10/CD123/CD25/CD200. The BRAFV600E mutation was negative, confirming the diagnosis of hairy cell leukemia-variant (HCL-v).
Lymphocytosis, villi, and nucleoli: a variant of hairy cell leukemia
Image: ASH Image Bank