INTEROBSERVER VARIABILITY IN THE DIAGNOSIS OF HIGH-GRADE PROSTATIC INTRAEPITHELIAL NEOPLASIA AND ADENOCARCINOMA

High-grade prostatic intraepithelial neoplasia (PIN) is a strong predi ctor of carcinoma when identified in small-needle biopsy specimens. Ho wever, the diagnostic variability of PIN is unknown. Eight pathologist s reviewed 321 prostatic biopsy specimens to assess the variability of the diagnosis of high-grade PIN and carcinoma. All of the specimens w ere classified as negative, high-grade PIN, suspicious for high-grade PIN, carcinoma, or suspicious for carcinoma; more than one diagnosis w as permitted, except for negative, We compared diagnoses made by two o bservers by pairing them for negative versus high-grade PIN, negative versus carcinoma, high-grade PIN versus carcinoma, and all diagnostic categories together, Mean kappa coefficent values for 28 interobserver combinations were 0.451, 0.845, 0.669, and 0.482, respectively, for e ach of the four comparison combinations considered, Our results indica te a high level of agreement, ''almost perfect'' (kappa = 0.81-1.0) fo r carcinoma, ''moderate'' (kappa = 0.41-0.60) for high-grade PIN, and ''substantial'' (kappa = 0.61-0.81) for high-grade PIN versus carcinom a. We found that variability was related to the level of interest in p rostatic pathology, the conditions of the study, the subjective applic ation of diagnostic criteria, and the influence of peers and clinical colleagues.