Marginal zone B-cell lymphoma.

(A) Nodal peri- and interfollicular infiltration by monocytoid B-cells with clear cytoplasm (HE × 60). (B) Nodal perisinusoidal infiltration by small tumoral B-cells with plasmacytic differentiation (HE × 400). (C) Splenic perifollicular infiltration surrounding the residual white pulp follicles, with typical “marginal-zone” pattern (HE × 60). (D) Splenic nodular infiltration with colonization of the white pulp by the tumoral cells associated with a diffuse invasion of the sinuses in the red pulp (HE × 60).