[Missed diagnosis in prostate incidental carcinoma]

522 cases of benign prostate hyperplasia from 1980 to 1994 were reviewed. Prostate incidental carcinoma (PIC) was identified in 26 cases (4.98%). In order to study the pathomorphological features and to study the causes for missed diagnosis of this entity, the authors observed and analysed the numbers of carcinomatous foci their distribution, classification, staging and differentiation, morphological features and prostate specific antigen (PSA) markers. It was found that 23 cases exhibited a pathological structure of uniform pattern and 3 cases with pluriform pattern. Adenocarcinoma was most common. 17 cases were A1 stage and 9 cases were A2 stage. Isolated multiple foci of invasion and alterations of architecture are important pathological features of these cases. Missed diagnosis of prostate cancer is related to the small amount of biopsy tissue, contrast between benign and malignant prostate epithelial tissue not distinct, scarce nuclear anaplasia, careless microscopic observation, or observer lacks the ability to differentiate between pathologic types and pluriform patterns. Different PSA reactions may be related to tumor differentiation and classification.