Nongynecological endometriosis presenting as an acute abdomen

Endometriosis is a highly prevalent disease that affects up to 10 % of menstruating women. Patients commonly present with pelvic pain or infertility, although the range of clinical symptoms varies widely. Affected women may be asymptomatic or experience mild, moderate, or severe pain that fluctuates with hormonal cycles. Patients who suffer extreme pain may seek immediate care and present to the emergency department with clinical signs of an acute abdomen. In the case of patients without a prior history of endometriosis, the differential diagnosis is broad and making the correct clinical and radiologic diagnosis in the emergency setting can be challenging. In some cases, the diagnosis is only made after surgical or histopathological analysis. Prompt and accurate clinical and radiological evaluation is necessary because complications of endometriosis, such as bowel obstruction and appendicitis, may require immediate surgical intervention. This pictorial essay analyzes nongynecological manifestations of endometriosis that may have a clinical presentation of an acute abdominal emergency. Atypical clinical presentations and unusual sites and complications of endometriosis are discussed, as well as the differential diagnostic considerations. The radiologic features of endometriosis are shown on multiple modalities, including computed tomography, magnetic resonance imaging, and ultrasound.