(A) Bone marrow aspiration showing few atypical mononuclear cells (arrow) with scanty cytoplasm and vacuolations and occasional cells with prominent nucleoli (Leishman stain). (B-D) Trephine biopsy revealing a hypercellular marrow with diffuse infiltration by medium-to-large cells with scanty cytoplasm, vesicular nuclei with irregular nuclear membrane and occasional cells showing prominent nucleoli.