Atrophic and Microcystic Limited Prostatic Adenocarcinomas

Atrophic carcinoma and microcystic carcinoma have previously been classified as variants of conventional acinar adenocarcinoma. In this article, we studied 4 cases of atrophic carcinoma and 4 cases of limited microcystic carcinoma. We found an incidence of 0.8% in 250 needle prostatic biopsies and 1.3% of atrophic carcinoma in 150 radical prostatectomies. Microcystic carcinomas were found in 3 prostatectomies (1.2%) and in 1 needle biopsy (0.67%). The useful histological criteria for atrophic carcinoma included the irregular disposition of the glands, infiltrative pattern, "rigid" luminal borders, and intraluminal secretions. Cytological changes included scant cytoplasm, nucleomegaly, hyperchromatic nuclei, and visible nucleoli. The glands of the microcystic carcinoma differ from the benign glands because the malignant ones show a markedly greater dilatation and exhibit rigidity of glandular lumens. In some cases of microcystic carcinoma, the nuclei were flattened, small, and hyperchromatic; therefore, they can be difficult to recognize as malignant.

False-Negative Histopathologic Diagnosis of Prostatic Adenocarcinoma

Context.—

Histopathologic diagnosis of adenocarcinoma of the prostate is based on light-microscopic examination of hematoxylin-eosin–stained tissue sections. Multiple factors, including preanalytic and analytic elements, affect the ability of the pathologist to accurately diagnose prostatic adenocarcinoma. False-negative diagnosis, that is, failure to diagnose prostatic adenocarcinoma, may have serious clinical consequences. It is important to delineate and understand those factors that may affect and cause histopathologic false-negative diagnoses of prostatic adenocarcinoma.

Objectives.—

To review common factors involved in histopathologic underdiagnosis of prostatic adenocarcinoma, including the following: (1) tissue processing and sectioning artifacts, (2) minimal adenocarcinoma, (3) deceptively benign appearing variants of acinar adenocarcinoma, (4) single cell adenocarcinoma, and (5) treatment effects.

Data Sources.—

Data sources included published, peer-reviewed literature and personal experiences of the senior author.

Conclusions.—

Knowledge of the reasons for histopathologic false-negative diagnosis of adenocarcinoma of the prostate is an important component in the diagnostic assessment of prostate tissue sections. Diagnostic awareness of the histomorphologic presentations of small (minimal) adenocarcinoma; deceptively benign appearing variants including atrophic, foamy gland, microcystic, and pseudohyperplastic variants; single cell carcinoma; and treatment effects is critical for establishment of a definitive diagnosis of adenocarcinoma and the prevention of false-negative diagnoses of prostate cancer.