Primary cutaneous diffuse large B-cell lymphoma, leg type and secondary cutaneous involvement by testicular B-cell lymphoma share identical clinicopathological and immunophenotypical features

BackgroundPrimary cutaneous diffuse large B-cell lymphoma (PCDLBCL), leg type can eventually disseminate to extracutaneous sites including testes. In addition, patients with testicular lymphoma can develop specific skin involvement.ObjectiveWe sought to describe similarities between PCDLBCL, leg type and testicular B-cell lymphoma affecting the skin.MethodsWe report two cases with typical clinicopathological and immunophenotypical features of leg type lymphoma occurring simultaneously with a testicular B-cell lymphoma. We also report an additional case of PCDLBCL, leg type with secondary testicular involvement.ResultsAll cases presented with typical red tumors exclusively located on the legs. Histologically, all cases showed a diffuse nonepidermotropic infiltrate composed of large blastic cells mainly centroblastic type. Phenotype showed strong positivity for Bcl-2, MUM-1, and FOXP1. Epstein-Barr virus stains and CD30 were negative in the 3 cases. In all cases the testicular infiltration showed the same pathological and phenotypical changes to those observed in the skin.LimitationsThis was a retrospective case series study.ConclusionSkin involvement by testicular B-cell lymphomas and PCDLBCL, leg type are indistinguishable on the basis of pathologic and immunophenotypical features, therefore specific investigation and clinic correlation are needed.