Signet ring cell adenocarcinoma of prostate.

Primary signet ring cell adenocarcinoma of the prostate is a rare malignancy with a total of 13 cases reported to date in the English literature. We report a very unusual case of signet ring adenocarcinoma of the prostate occurring in a patient who presented initially with irritative voiding symptoms and a bladder mass. Results of immunohistochemical, flow cytometric, and cytogenetic analyses of the tumor are presented.