[Pathomorphologic features of clinical stage A prostate carcinoma and causes for misdiagnosis and missed diagnosis].
OBJECTIVE: To study the pathomorphologic features and causes for misdiagnosis and missed diagnosis of clinical stage A prostate carcinoma. METHODS: Prostate samples from a series of 1 020 prostate resections performed in five Shanghai hospitals were obtained, from which 50 clinical stage A carcinoma were studied by immunohistochemistry, according to tumor differentiation and their volume, they were divided into stage A1 and A2 disease. The pathomorphologic features of stage A1 and A2 disease were compared, and the causes for misdiagnosis were analysed. RESULTS: Stage A1 cancer were well- or moderately well-differentiated, of low volume and tended to be multifocal; Stage A2 cancers were poorly differentiated, of high volume, diffuse infiltration and with high grade prostatic intraepithelial neoplasia. 8 cases were misdiagnosed of which 7 cases were stage A1 and misdiagnosed as benign proliferous small gland lesions and 1 case of A2 disease was misdiagnosed as epithelioid histiocytic reactive proliferation. CONCLUSIONS: Stage A1 cancer tended to be initiated in the transition zone and the central zone of the hyperplastic prostate. Stage A2 cancers were mostly middle grade to high grade cancers initiated in the peripheral region and then invaded the central area. The lower incidence of stage A carcinoma in China is related to the small amount of biopsy tissue, careless microscopic observation, or lack of the ability to diagnose stage A1 cancer.