Monarch Disease Ontology identifier MONDO_0005193 (prostate intraepithelial neoplasia) is a neoplastic proliferation of the epithelial cells that line the acini and the ducts of the prostate gland. The neoplastic epithelial cells are confined within the acini and the ducts and they do not invade the surrounding prostatic stroma. Morphologically, it is classified as low or high grade. Also known as: PIN, pin, pin - prostatic intraepithelial neoplasia, prostate intraepithelial neopl., prostate intraepithelial neoplasia (pin), prostatic intraepithelial neoplasia.