Morphometric analysis of borderline atypia in prostatic aspiration biopsy specimens.

In a prior study of 411 fine needle aspirates of the prostate (FNAPs), we identified a subset of 50 (12%) aspirates in which the findings were designated cytologically atypical. These equivocal cases formed a heterogeneous group composed of both histologically benign and malignant proliferations in which cutting needle biopsy was necessary to further delineate the nature of the abnormality. In an attempt to define quantitative and morphologic criteria for the separation of these proliferations into benign and malignant categories and to reduce the need for diagnostic cutting needle biopsies, we performed a cytomorphometric analysis of smears from 12 FNAPs (6 histologically proven benign and 6 histologically proven malignant) with equivocal cytologic atypia. We were unable to define any cytomorphometric criteria that accurately subdivided these cases into benign and malignant categories.