Abstract
A 70-year-old woman visited a nearby clinic with a 1-week history of persistent left back pain. Chest X-ray indicated lifting of the left diaphragm and inflammatory response was also found to be elevated, so she was referred to our hospital for detailed examinations and medical attention. On presentation, blood tests showed a significantly increased inflammatory response, and imaging showed free air on the liver surface and a cavitary mass with a liquid surface under the left diaphragm. The possibility of gastrointestinal perforation was considered, but neither upper nor lower gastrointestinal endoscopy confirmed any perforations, and no findings suggesting any other infectious source were observed, so subphrenic abscess of unknown etiology was diagnosed. Percutaneous intraperitoneal drainage was performed and antibiotics were administered, with continued conservative treatment. Symptoms alleviated and she was discharged. Causes of subphrenic abscess could include gastrointestinal perforation, cholecystitis, or pancreatitis, but rarer causes have been reported, including ectopic Meckel's diverticulum and ectopic appendicitis. The present case was considered idiopathic, with unknown etiology, but medical attention needs to be provided with rare diseases in mind when a cause is being sought.
