Giant solitary tumor in the true pelvis: atypical prostatic adenomyomatosis.

We report about a 32-year-old patient presenting with a large pelvic mass. Sonographic and radiological findings were inconclusive. Open tumorectomy of the mass weighing 500 g was performed. Intraoperative fresh-frozen sections revealed no clear signs of malignancy. Decisive histology and immunohistochemistry led to the diagnosis of benign ectopic prostatic adenomyomatosis. The histology and possible etiologies of this rare finding are discussed.