Pseudohyperplastic Adenocarcinoma of the Prostate

Abstract

A 60-year-old man underwent radical prostatectomy after a needle biopsy diagnosis of adenocarcinoma of the prostate with Gleason score 3 þ 3 1⁄4 6 in 4 of 12 cores. Sections of radical prostatectomy tissue showed areas with a somewhat nodular growth of complex glands resembling benign prostatic hyperplasia (fig. 1). This proliferation represents an uncommon variant of usual acinar adenocarcinoma of the prostate known as pseudohyperplastic adenocarcinoma, so called because the light microscopic appearance can simulate that of epithelial hyperplasia in the prostate. This variant, along with other deceptively benign appearing variants (atrophic and foamy gland adenocarcinomas), constitutes a large percentage of needle biopsy cases misdiagnosed as benign. There are no known clinical, radiological or gross features specific for pseudohyperplastic prostatic adenocarcinoma. Microscopically, pseudohyperplastic adenocarcinoma shows papillary infolding (fig. 2), luminal undulations and branching, and cystic dilatation. Pseudohyperplastic prostatic adenocarcinoma in the whole gland may be localized