Composite Follicular Lymphoma and CD5-Positive Nodal Marginal Zone Lymphoma.

Composite CD10-positive low-grade B-cell and CD5-positive low-grade B-cell lymphoma is extremely rare. We report a case of a composite follicular lymphoma (FL) and CD5-positive nodal marginal zone lymphoma (NMZL) in a resected inguinal lymph node of a 72-year-old Japanese male. Histologically, multiple follicles had reactive-germinal centers with tingible body macrophages, a thin mantle zone and a wide marginal zone. The wide marginal zone consisted of medium-sized cells having slightly indented nuclei and clear cytoplasm, indicating monocytoid cells with CD5-positive B-cells. Several follicles had germinal centers filled with many centrocytes, with CD10-positive B-cells. Polymerase chain reaction/sequence analysis of the immunoglobulin heavy chain gene obtained from microdissected regions of CD5-positive NMZL and FL showed different sequences within the CDR3 region. To our knowledge, this is the first report of FL and CD5-positive NMZL.