Case Report: a rare case of small cell carcinoma of the prostate.

Small cell carcinoma of the prostate is an uncommon malignancy with an aggressive clinical course. Its non-specific symptoms and frequently normal prostate-specific antigen (PSA) levels can make early diagnosis difficult. We report a 74-year-old man with progressive defecation difficulty and prostate enlargement. Although his serum PSA was within the normal range, imaging revealed a prostate mass suggestive of local invasion. Needle biopsy established the diagnosis of small cell carcinoma with neuroendocrine marker expression. He later received etoposide plus cisplatin chemotherapy but deteriorated soon after treatment began and died despite resuscitation. This case underscores the importance of early biopsy when imaging suggests an invasive prostate mass, even if PSA is not elevated.