ABSTRACT
Primary tumors of the seminal vesicle are rare; most reported cases are carcinomas, with occasional reports of primary seminal vesicle sarcoma and an uncommon group of mixed epithelial-stromal tumors. The latter have been variably reported in the literature as cystadenoma, phyllodes tumor, and mullerian adenosarcoma-like tumor. We describe a 37-year-old man who presented with symptoms of bladder outlet obstruction and was found to have a pelvic mass. Resection of the mass yielded a biphasic tumor characterized by cystically dilated glandular spaces admixed with spindle-shaped stromal cells. There was no significant cytologic atypia or mitotic activity. The histologic features are most consistent with the reported cases of cystadenoma. The patient is alive, with no evidence of disease, 6 months after surgery. This case adds to the gradually growing body of literature on mixed epithelial-stromal tumors of the seminal vesicle.