Adenoid cystic carcinoma of the urethra/Cowper's gland with concurrent high-grade prostatic adenocarcinoma: a detailed clinicopathologic case report and review of the literature.

Primary adenoid cystic carcinoma of the urethra is uncommon with only 9 cases reported in the medical literature; all tumors arose from Cowper's glands. Herein, we report the histological features and immunohistochemical characteristics of 1 patient with primary adenoid cystic carcinoma involving the entire posterior urethra, prostate gland, corpus spongiosum, corpora cavernosa, urogenital diaphragm, perianal soft tissue, and muscularis propria layer of rectum. We also review other published cases to evaluate the prognosis and treatment.