Postoperative Metachronous Metastasis of Bladder Cancer to Penis: A Case Report

Penile metastases are extremely rare events, originating primarily from primary pelvic tumours of the prostate, bladder, and gastrointestinal tract. The underlying mechanism of bladder cancer metastasis to the penis remains unclear. Metastasis to the penis is usually considered a late manifestation of systemic spread. Therefore, the prognosis of patients with penile metastasis remains poor and their survival period is short. Therefore, reporting this rare case will help to better understand the characteristics, diagnosis, and treatment processes of the disease, with the aim of improving the accuracy and efficiency of diagnosis and treatment.

A 65-year-old male received transurethral resection of a bladder tumor. One year later, he underwent radical cystectomy because of the recurrence and progression of bladder cancer. Postoperative pathology demonstrated that the stage of bladder cancer was T₃N₀M₀. One year later, he discovered a penile mass that gradually grew and became hard, accompanied by urinary retention, but without other clinical symptoms. The patient underwent a complete penectomy. Histopathology and immunohistochemistry results demonstrated the tumour's origin as a bladder urothelial carcinoma. The patient received systemic chemotherapy after surgery, but died 7 months later.

Although penile metastasis of bladder cancer typically indicates an advanced stage of the malignant tumour and poor prognosis, we recommend that male patients with a history of bladder cancer should undergo a regular clinical examination of the penis to rapidly detect the disease and receive early treatment. In this case, despite treatment measures such as systemic chemotherapy and penectomy, the patient's prognosis remained poor.