A 55-year-old African-American man with clinical stage T1c prostate cancer underwent prostatectomy. Non-caseating, epithelioid granulomata adjacent to the anterior fibromuscular stroma were found incidentally. The granulomata included Langhans giant cells with rare conchoidal bodies. The distribution of the granulomata was not that of non-specific granulomatous prostatitis centred around ducts and glands. By immunohistochemistry, the epithelioid cells were positive for angiotensin-converting enzyme. The histological appearance suggested sarcoidosis, which was confirmed by the clinical history. Four years earlier, the patient had been treated for sarcoidosis.