Signet ring cell prostatic intraepithelial neoplasia is a rare speculated variant of high-grade prostatic intraepithelial neoplasia (HGPIN). Here, we present a free-standing and isolated signet ring cell HGPIN that was not associated with invasive carcinoma on needle biopsy and demonstrated the existence of this type of HGPIN variant. The differentiation between HGPIN and intraductal carcinoma of prostate is also discussed.
Keywords: PIN; intraductal carcinoma; prostate cancer; signet ring.