SIGNET-RING CARCINOMA OF THE PROSTATE

A case of prostatic signet-ring adenocarcinoma is described in a man w ith a history of open prostatectomy for prostate carcinoma (18 years p reviously). Immunostaining confirmed the prostatic origin of the signe t-ring tumor which stained for prostatic acid phosphatase (PSAP) and p rostate specific antigen (PSA). Cytokeratin immunostaining showed the vacuoles to be true lamina with clear and distinct outlines, the featu re confirmed by ultrastructural examination. This aggressive tumor is an uncommon but distinct variant of primary prostatic carcinoma which should be distinguished from artefactual vacuolation of tumor, inflamm atory and stromal cells, and metastatic disease.