SPREAD OF ADENOCARCINOMA WITHIN PROSTATIC DUCTS AND ACINI - MORPHOLOGIC AND CLINICAL CORRELATIONS

Malignant epithelial masses within prostatic duct lumens have been equ ated with several conflicting entities, including Gleason cribriform g rade 3 carcinoma and cribriforming dysplasia, We identified 51 radical prostatectomy cancers containing intraductal lesions among 130 cases, with total cancer volumes between 4 and 10 cc. Such lesions with duct lumen-spanning septa or masses were rare in areas away from invasive cancer (22 foci), while dysplasia (prostatic intraepithelial neoplasia ) was common (1,490 foci). Consequently, these lesions were interprete d as being part of the evolution of invasive carcinoma rather than pre cursors; they were designated ''intraductal carcinoma'' as distinct fr om dysplasia. Intraductal cancer areas within invasive carcinoma usual ly represented cancer extension within the branches of a single segmen t of the duct-acinar system from near the urethra to the gland capsule . In 51% of cases with intraductal spread, the invasive component prod uced large (>0.5 mm) tumor masses in perineural spaces, which in turn correlated strongly with extensive capsule penetration and frequent po sitive surgical margins selectively at the superior nerve pedicle. The amount of grade 4/5 cancer, the amount of intraductal carcinoma, and the large perineural tumor mass appeared to be related to postprostate ctomy progression of cancer, as measured by elevation of ultrasensitiv e serum prostate-specific antigen. It was concluded that intraductal p rostatic adenocarcinoma is a common morphologic entity with precisely defined histologic criteria and a unique biologic significance, as ref lected by an enhanced capacity for extensive spread within ducts and p erineural spaces. It was proposed that the diversity of diagnoses atta ched to most cribriform malignant lesions can be unified by the concep t of this single entity.