Etymed
hairy cell leukemia
Definition
A rare, indolent B-cell lymphoid neoplasm characterized by pancytopenia, splenomegaly, and the presence of small mature B lymphocytes with irregular cytoplasmic projections ("hairy" appearance) in the peripheral blood and bone marrow. Strongly positive for BRAF V600E mutation.
Clinical context
A 55-year-old male presents with fatigue, recurrent infections, and early satiety. Physical examination reveals massive splenomegaly extending to the pelvis and no lymphadenopathy. CBC shows pancytopenia: WBC 1.8 x10^9/L, hemoglobin 9.5 g/dL, platelets 65 x10^9/L. Peripheral blood smear shows lymphocytes with circumferential cytoplasmic projections giving a "hairy" appearance. Flow cytometry is positive for CD19, CD20, CD25, CD103, and CD123. Bone marrow biopsy reveals a "dry tap" with diffuse infiltration and characteristic "fried egg" pattern on reticulin stain. BRAF V600E mutation is confirmed. Treatment with cladribine (2-CdA) achieves complete remission.
Mnemonic
HAIRY (hair-like projections) + CELL + LEUK (white) + EMIA (blood) = white blood cells with hairy projections. Remember: "Hairy cells love the spleen" — massive splenomegaly without lymphadenopathy. TRAP stain positive, BRAF V600E.
These morphemes also unlock…
- hairy — covered with hair-like projections
- cell — small room; basic biological unit (from cella)
- leuk/o — white (from leukos)
- -emia — blood condition