Renal-type clear cell carcinoma occurring in the prostate.

Clear cell lesions of the urinary tract often present diagnostic challenges. We report a previously undescribed lesion in the prostate, occurring in a 73-year-old man who presented with hematuria and subsequently underwent transurethral resection of the prostate. A total of 24 g of tissue was removed, and in 4 of 17 blocks submitted a lesion morphologically and immunohistochemically similar to clear cell carcinoma of the kidney was noted. A thorough cystoscopic and full-body, radiologic workup was performed, but no renal tumor was discovered. Random cystoscopic biopsies of the bladder and prostatic urethra as well as bladder washings were benign. Subsequent needle biopsies of the prostate were also benign. The patient underwent a pelvic lymph node dissection with radical cystoprostatectomy and orthotopic Studer pouch diversion. There was organ-confined, ordinary-type prostatic adenocarcinoma (Gleason's 3 + 3) present bilaterally in the peripheral zone; no residual clear cell carcinoma was identified. All lymph nodes were negative, and the urinary bladder showed no dysplasia or neoplasia. We think this tumor represents a primary renal type of clear cell carcinoma arising in the prostate. To our knowledge, this type of tumor has not been previously reported to arise in an extrarenal location.