CD 19 positive, CD22 positive, CD103 positive monoclonal B-cells with bright kappa positivity were found to comprise 60% of the peripheral blood lymphoid cells on flow cytometric analysis in a 55 year old man with massive splenomegaly and a total leucocyte count of 3.3 x 109/L. Which one of the following is the most likely diagnosis?
High-Yield Explanation
Answer is D (Hairy cell leukemia) Presence of massive splenomegaly, and granulocytopenia, alongwith characteristic immunophenotypic features (specially CD103) suggests the diagnosis of Hairy cell leukemia. CD103 is exclusively positive in Hairy cell leukemia and thus leaves no doubt as regards the correct diagnosis.