A 40-year-old woman presented to the emergency department with increasingly sharp abdominal pain in the left lower quadrant of 10 days' duration. Bowel movements were normal, the patient was afebrile, and blood test results, including a white blood cell count, were unremarkable. The physical examination showed localized pressure and percussion pain in the left lower abdomen. The patient reported that the same pain had appeared sporadically over the past 3 years, approximately twice a month and mostly during the night. She had been examined several times by a gynecologist without any pathologic findings. In addition, she had undergone a colonoscopy that revealed no abnormal findings.