[Marfan syndrome complicated with CD5+ CD10+ diffuse large B-cell lymphoma].

Marfan syndrome (MFS) is caused by mutations in the gene encoding fibrillin. A 35-year-old man with MFS visited a local physician because of a sore throat. His left tonsil gradually became swollen and he was referred to our department. Histopathological examination of tonsil biopsy specimens showed diffuse proliferation of lymphoma cells with large nuclei. The tumor cells showed CD5+, CD10+, CD20+, BCL-6+, and MUM-1-. Based on these findings, the patient was diagnosed with CD5+ CD10+ diffuse large B-cell lymphoma (DLBCL). Chemotherapy combined with rituximab was administered and complete response was achieved. CD5+ DLBCL comprises approximately 5 approximately 10% of DLBCLs. In addition, CD5+ CD10+ DLBCL comprises about 5% of CD5+ DLBCLs. There may be a relationship between MFS and B-cell lymphoma because mutations in the gene encoding the receptor of transforming growth factor-beta (TGF-beta) have been implicated in the pathogenesis of MFS and downregulation of TGF-beta receptor expression has been described in the pathology of B-cell lymphoma.