[A Case of High‒Grade Appendiceal Mucinous Neoplasm Undergoing Ileocecal Resection].

A 75‒year‒old man consulted our hospital with abdominal pain and fever. He was diagnosed as abscess‒forming appendicitis by contrast‒enhanced computed tomography(CT), and underwent conservative treatment and CT‒guided drainage. CT‒guided drainage revealed no abscess. Follow‒up contrast‒enhanced CT and MRI revealed a diagnosis of appendiceal mucinous neoplasm and peritoneal pseudomyxoma. Hence, the treatment strategy was operation. Intraoperative findings revealed mucus deposits in the right paracolic gutter and around the liver. The mucus was examined cytologically, but no malignant findings were detected. An ileocecal resection was performed. The pathological diagnosis was high‒grade appendiceal mucinous neoplasm(HAMN). The patient was discharged without postoperative complications. The patient was alive and recurrence‒free, 12 months after surgery. We report this rare case with a review of the literature.