Periprostatic subendothelial intravascular granulomatosis: a mimic of high-grade intravascular prostatic adenocarcinoma.

A rare case of intravascular granulomatous inflammation mimicking intravascular prostatic adenocarcinoma is reported. To the author's knowledge, there have been no previous reports of prostatic or periprostatic intravascular granulomatous inflammation. A 67-year-old man presented with elevated serum prostate specific antigen (PSA) and was found to have a high-grade adenocarcinoma of the prostate. A radical prostatectomy revealed intravascular subendothelial granulomatous inflammation mimicking vascular invasion of a high-grade adenocarcinoma found elsewhere in the prostate. Immunoperoxidase stains confirmed that the subendothelial infiltrate was composed of histiocytes and not tumor cells. Periprostatic subendothelial intravascular granulomatosis is a rare event, which may mimic vascular involvement of high-grade prostatic adenocarcinoma and may result from a previous needle biopsy of the prostate. Possible mechanisms for this finding are discussed. It is important to distinguish this process from high-grade prostatic adenocarcinoma involving blood vessels for obvious clinical reasons.