Postatrophic hyperplasia of the prostate gland - A detailed analysis of its morphology in needle biopsy specimens

Postatrophic hyperplasia is a histologic pattern showing atrophic and hyper plastic glands, sometimes with a small acinar configuration. Because distin ction from small acinar carcinoma may be challenging, particularly in needl e biopsy specimens, we studied 56 needle biopsy specimens containing 68 foc i to ascertain the morphologic spectrum of postatrophic hyperplasia. All fo ci showed a distinct lobular small acinar proliferation with varying propor tions of atrophic and hyperplastic glands. Gland size was typically variabl e, predominantly of small caliber but occasionally of intermediate to large r caliber. Round, oval, elongated, slitlike and stellate glands were seen. The nuclei were generally regular without hyperchromasia, with rare small n ucleoli seen in 10 (15%) foci. The cytoplasm was variable, ranging from sca nt in atrophic glands to moderate or abundant and clear or occasionally eos inophilic in hyperplastic glands. An irregular internal gland contour was n oted in glands with features of both atrophy and hyperplasia. Basal cells w ere apparent by light microscopy in most foci, although their distribution within foci and between foci varied. This finding was confirmed in all 26 c ases studied with the high molecular weight cytokeratin immunohistochemical stain (34 beta E12). Associated pathology included adenocarcinoma (12%), h igh-grade prostatic intraepithelial neoplasia (3%), atrophy distinct from f oci of postatrophic hyperplasia (55%), and atypical adenomatous hyperplasia (2%). Adjunctive features of cancer were not seen in any of the foci of po statrophic hyperplasia. Familiarity with the histologic features of postatr ophic hyperplasia will allow its confident separation from cancer, especial ly in limited biopsy material.