Metastatic Adenocarcinoma of the Prostate Presenting as a Penile Mass in a Patient With Acute Urinary Retention: A Case Report

Metastatic prostate adenocarcinoma presenting as a penile lesion is extremely rare and can mimic primary penile malignancies. A 72-year-old male presented with acute urinary retention and a painless penile lesion with phimosis. The lesion had gradually enlarged over six months with intermittent bleeding. Examination revealed a 3 cm ulcerated mass on the glans near the coronal sulcus. A wedge biopsy suggested adenosquamous carcinoma. CT showed no distant metastases. The patient underwent total penectomy with perineal urethrostomy. Histopathology revealed malignancy with clear margins. Further evaluation at a major tertiary health care centre, including immunohistochemistry, confirmed metastatic prostatic adenocarcinoma (NKX3.1, PSA positive; CK7, CK20, CDX2 negative). Serum prostate-specific antigen (PSA) was elevated (37.8 ng/mL), and prostate-specific membrane antigen positron emission tomography (PSMA PET) confirmed metastasis. The patient was treated with androgen deprivation therapy (bilateral orchidectomy), abiraterone, and docetaxel.