Renal-type clear cell carcinoma of the prostate: A case report.

Renal-type clear cell carcinoma of the prostate is a rare and novel tumor that has only been identified in recent years. The present study describes a lesion in the prostate of a 64-year-old male with a two-year history of urinary frequency, urgency and difficulty, who was admitted to the San Ai Tang Hospital for benign prostatic hyperplasia, and subsequently underwent transurethral resection of the prostate. In total, 12 g of tissue was resected, which demonstrated morphological and immunohistochemical similarities to clear cell carcinoma of the kidney. Ultrasound inspection and computed tomography revealed prostate enlargement. Although no renal-enclosed mass was identified, metastatic lesions were revealed in the lungs, sternum and clavicles. In addition, right pleural thickening and a small amount of effusion in the pleural cavity were detected. Clear cell carcinoma was identified throughout the prostate, with surrounding regions of ordinary-type prostatic adenocarcinoma (Gleason score, 4+4). The urinary bladder exhibited no dysplasia or neoplasia. It was therefore concluded that the tumor represented a primary renal-type clear cell carcinoma that had arisen in the prostate. To the best of our knowledge, this type of extra-renal tumor has only been reported in three other previous studies.