LOW-GRADE ADENOCARCINOMA SIMULATING BENIGN GLANDULAR LESIONS IN NEEDLE PROSTATIC BIOPSY

In order to define the frequency and morphological characteristics of low grade adenocarcinomas misdiagnosed as benign prostatic hyperplasia in needle prostatic biopsies, we reviewed 135 consecutive needle biop sies with prostatic cancer. In three biopsies (2.2%) low grade adenoca rcinoma was found as a single neoplastic pattern simulating benign hyp erplastic glands in some histological fields and prostatic adenosis in others. These biopsies showed the histological features described for carcinomas originating in the transition zone and were seen in isolat ed histological fields. Retrospectively, it was found that these biops ies showed features of adenocarcinoma although some histologic criteri a of malignancy such as infiltrative pattern, prominent nucleoli and n uclear enlargement were seen only focally. Blue mucinous secretions, c rystalloids, occasional stromal single cells and mitotic figures were absent. We conclude that a detailed analysis of architectural and cyto lgical features must be made of all glandular proliferations, since th is type of low grade adenocarcinoma can occasionally be found in needl e prostatic biopsies as the only neoplastic pattern in needle biopsy s pecimens and simulate benign glandular lesions.