A 40 year male presented with massive splenomegaly. There was mild hepatic enlargement also. Peripheral blood film shows cells with hair like projections; which are positive for CD 25 and CD 103 and negative for CD 23. The likely diagnosis is a :: (A) Precursor B - cell neoplasm, (B) Peripheral B - cell neoplasm, (C) Precursor T-cell neoplasm, (D) Peripheral T-cell neoplasm
Answer is B. Peripheral B - cell neoplasm Hairy cells on peripheral blood smear and CD 103 positivity are diagnostic of hairy cell leukemia which is a peripheral B cell neoplasm.