Iatrogenic pulse granuloma detected at prostatectomy.

Pulse granulomas are peculiar reactions to vegetable matter characterized by aggregates of hyaline rings and may be oral or extraoral. Pulse granulomas are important to recognize because they may indicate serious pathologic processes, may simulate neoplasia clinically, and may morphologically be confused with hyaline vasculopathy. We recently encountered a case involving a highly unusual pulse granuloma in a 55-year-old man who underwent prostatectomy for adenocarcinoma. Prior pancolonoscopy and digital rectal examination excluded significant colorectal disease. Microscopy showed a prominent pulse granuloma with demonstrable vegetable matter occupying periprostatic soft tissue. Interestingly, retrospective review of material from prior prostatic core biopsies revealed vegetable matter that appeared identical to the vegetable matter in the pulse granuloma. We conclude that the biopsies transrectally displaced vegetable matter, which provided the nidus for the pulse granuloma. We present the first pulse granuloma to be caused by a biopsy or to occupy periprostatic soft tissue.