[A case of urachal abscess accompanied by a stone].

A 64-year-old woman presented to our hospital with the chief complaints of abdominal pain and appetite loss, and she was admitted to the internal medicine department. Kidney, ureter and bladder X-ray revealed intrapelvic calcification near the bladder, and so, the patient consulted our department. Computed tomography and magnetic resonance imaging revealed an urachal abscess accompanied by a stone. Open surgery was performed under general anesthesia. The mass adhered tightly to the intestine and bladder. The urachal abscess ruptured during the operation, and pus leaked into the intraabdominal cavity. Partial cystectomy was performed to remove the mass completely. The stone existed in the urachal abscess, and its constituents were CaOxa (51%) and CaP (49%). The pathological diagnosis was urachal abscess without malignancy.