[Signet ring cell carcinoma of the prostate successfully treated with endocrine therapy: a case report].

A 67-year-old man complained of dysuria. The prostate was enlarged and stony hard. The serum level of prostate specific antigen was abnormally high (46.2 ng/ml). Prostatic biopsy showed signet ring cells which were stained positive for prostate specific antigen and poorly differentiated adenocarcinoma. Computed tomographic scan revealed the enlargement of the para-aortic lymph nodes. Endocrine therapy with luteinizing hormone-releasing hormone agonist was started. After two months, the serum level of prostate specific antigen decreased to the normal range. The pathological findings and the good response to endocrine therapy in our case suggest that signet ring cell carcinoma of the prostate is only a morphologic variant of ordinary prostatic adenocarcinoma.