Coexisting mantle cell lymphoma and prostate adenocarcinoma.

Prostatic mantle cell lymphoma (MCL) is a very rare entity with only 5 reported cases in the literature. We report a case of coexisting MCL and prostate adenocarcinoma (PCa) in an elderly male and review the morphologic features of classic and rare prostatic MCL subtypes. Careful morphologic evaluation and immunohistochemical findings of positive CD5, CD20, and cyclin D1 and negative CD23 and CD3 can guide us to the diagnosis of MCL. Given the fact that transurethral resection of prostate is done quite routinely, this paper draws attention to the manner in which long standing bladder outlet obstruction and postbiopsy prostate specimens with dense lymphoid infiltration can masquerade as lymphoma. It highlights the importance of exercising care while reviewing prostate specimens with evidence of chronic prostatitis so as not to miss this rare neoplasm.