Uterus-like mass: A very rare and elusive entity a case report

Uterus-like mass (ULM) is an extremely rare lesion. Gross morphology of ULM resembling a uterus. It can occur in various organs in the abdominal cavity, even in the spinal cord. The histogenesis of ULM remains uncertain. A number of hypotheses have been proposed including metaplasia, congenital anomaly, and heterotopia theory.

We describe a case of 43-year-old male presented with a complaint of acute low abdominal pain. Pelvic ultrasound found a large pelvic mass embedded in the broad ligament.

The mass contains a variable thickness smooth muscle layer lined with endometrial glands and stroma which resembling a uterus. Eventually, the patient was diagnosed as ULM by histopathological examination.

Except hypomenorrhea, the patient did not have any other associated abnormalities. We suggest this case supports the metaplasia theory that ULM is a benign mass formed by the proliferation of ectopic endometrial stromal cells or pluripotent mesenchymal cells of the 2nd Müllerian system.