Histologic findings in postcryosurgical prostatic biopsies

The increasing use of cryosurgical ablation of the prostate for prostatic carcinoma necessitates that surgical pathologists be aware of the cryosurgically induced histologic changes in the prostate. Twenty-one patients at our institution underwent prostatic cryosurgery, and 17 subsequently had follow-up biopsies. The Gleason combined scores ascribed to the original tumors were 4 (two patients), 5 (six patients), 6 (seven patients), 7 (one patient), and 8 (one patient). Histologic examination revealed residual carcinoma (four patients, with Gleason combined scores of 4, 5, 6, and 8), necrosis (all 17 patients), hyalinization (nine patients), fibrosis (nine patients), granulomatous inflammation (three patients), foci of calcification (eight patients), squamous metaplasia (four patients), transitional metaplasia (two patients), hemosiderin deposition (six patients), edema (two patients), bacterial colonization (one patient), and hemorrhage (one patient). The grade of residual carcinoma in all four patients was identical with the grade assigned before the cryosurgical ablation. The stroma surrounding the residual tumor did not display any postcryosurgical histologic changes, and we postulate that these areas were not adequately frozen. In conclusion, prostatic cryotherapy induces a variety of histologic changes in normal and diseased tissue.