Multilocular cystadenoma and cystadenocarcinoma of the prostate.

Background: Multicystic prostatic tumors are rare, with only a few reported cases of prostatic cystadenoma and cystadenocarcinoma in the scientific literature.

Methods: A retrospective review of our tumor registry over the last 25 years identified 2 rare cystic tumors of the prostate: 1 multilocular cystadenoma and 1 multilocular cystadenocarcinoma.

Results: The first case illustrates the clinical and pathologic features of prostatic multilocular cystadenoma. A 42-year-old man presented with a 16-cm suprapubic mass causing displacement of adjacent visceral organs. Pathologic examination after prostatectomy confirmed it to be a multilocular cystadenoma of the prostate. The patient's postoperative course was uneventful, and his serum prostate-specific antigen level remained at < or =0.04 ng/ml throughout the course of his disease. In the second case, we present an 80-year-old male presenting with a 12-cm cystic mass of the prostate. His serum prostate-specific antigen level remained at > or =9.0 ng/ml throughout the course of his disease. The tumor had an aggressive local growth pattern, with invasion into perirectal adipose tissue. This patient underwent a pelvic exenteration, followed by adjuvant systemic chemotherapy and complete androgen blockade. Despite aggressive treatment, he had 3 recurrences over 4 months but remains alive with disease at 23-month follow-up.

Conclusions: Cystadenocarcinoma of the prostate is locally aggressive and should be included in the differential diagnosis of cystic lesions of the prostate.