Prostate secretory granules in normal and neoplastic prostate glands: a diagnostic aid to needle biopsy

The recent increased efficacy of diagnosing prostate carcinoma from needle biopsy can be attributed to the accelerated biopsy rate as a result of cancer screening, the greater number of core samples per set, and the increased ability to identify malignancy in progressively smaller gland foci. This improvement in histological judgement has been facilitated by more sophisticated histological criteria, which in turn depend largely on an increasing knowledge of normal histological features and their abnormal counterparts. The recent discovery of the prostate secretory granule (PSG) as part of the normal secretory mechanism has prompted our study of the PSG as a possible additional criterion for distinction between benign and malignant cells in biopsy samples. The proper delineation of PSG required glutaraldehyde-based fixation, but this change in fixation showed additional diagnostic advantages. We quantitated PSG depletion in 150 sequential core biopsy samples, evaluating benign epithelium, dysplasia (PIN), Gleason grade 3, and grade 4 carcinoma separately. Overall, 80% of carcinomas and 63% of high-grade dysplasias were markedly depleted of PSG such that no granules were seen at low-power magnification with routine haematoxylin and eosin stains. This contrast between benign and malignant epithelium was especially prominent in small carcinoma foci greatly assisting in cancer recognition. Comparison between all groups showed an advantage of glutaraldehyde-based tissue fixation over formalin fixation for prostate needle biopsy specimens, providing clear resolution of cytological detail a well as an additional histologic criterion for cancer diagnosis. HUM PATHOL 31:1515-1519.