Atypical Intraductal Proliferation in Prostate Needle Core Biopsy: Validation as a Marker of Unsampled Adverse Pathology in a Clinicopathologic Series of 142 New Patients.

Atypical intraductal proliferation (AIP) of the prostate is characterized by morphologic features exceeding that of high-grade prostatic intraepithelial neoplasia but not meeting strict diagnostic criteria for intraductal carcinoma. We examined the clinical significance of AIP in biopsy specimens. Patients with AIP diagnosed on biopsy were identified from surgical pathology archives.