A postmenopausal woman in her mid-50s (gravida 2, aborta 2) with a known history of endometriosis and adenomyosis presented to the emergency department with severe abdominal pain that she rated 10 of 10 in intensity and which had developed suddenly 5 days before presentation. The abdominal pain was associated with diarrhea, nausea, and abdominal bloating. On examination, the patient was afebrile and her abdomen was soft and nondistended without guarding or rebound but tender in the left lower quadrant. The patient had a palpable nodule in the posterior vaginal fornix and fullness in the left lower quadrant of the abdomen on bimanual examination.