<prompt> A 63-year old man presented with massive splenomegaly, lymphadenopathy and a total leucocyte count of 17000 per mm3. The flow cytometery showed CD 19 positive, CD 5 positive, CD 23 negative, monoclonal B-cells with bright kappa positively comprising 80 of the peripheral blood lymphoid cells. The most likely diagnosis is:Mantle cell lymphomaSplenic lymphoma with villous lymphocytesFollicular lymphomaHairy cell leukemia  <response>: Answer is A Mantle cell lymphoma The given clinical profile is suggestive of mantle cell lymphoma as explained below. Mean Age 63 yrs Mantle cell lymphoma Presents in the middle aged and the elderly Clinical profile - Painless lymphadenopathy - Splenomegaly - Occasional GI involvement 