Clear cell cribriform hyperplasia of prostate. Report of 10 cases.

We report 10 patients with clear cell cribriform hyperplasia of the prostate. Their ages ranged from 62 to 87 years, with a mean of 72 years. The clinical diagnosis in all patients was benign nodular hyperplasia; all the patients are alive and have shown no evidence of recurrent disease. Follow-ups ranged from 1 month to 7 years (median: 12.5 months; mean: 24.6 months). Pathologically, this lesion has a cribriform arrangement of clear cells with a complex papillary growth simulating the cribriform pattern of prostatic carcinoma. In fact, in five of the 10 cases, the referring diagnosis was either carcinoma or possible carcinoma. Cytologically, however, there is no nuclear atypia, mitosis, or prominent nucleoli, and typically there is a double epithelial cell layer at the periphery of the involved acini. In summary, clear cell cribriform hyperplasia is a benign hyperplastic process with a complex papillary-cribriform structure and should not be confused with prostatic carcinoma. The key feature for the diagnosis is the preservation of nodular configuration with a bland cytology and double cell layer lining the involved acini.