Complete appendiceal intussusception induced by primary appendiceal adenocarcinoma in tubular adenoma: a case report.

A case of complete intussusception induced by appendiceal carcinoma is reported. The patient was a 49-year-old man complaining of rectal bleeding. Barium enema and colonoscopy revealed a cecal polyp; it was interpreted as an inverted appendix with a tumor. Computed tomography showed an invaginated appendix into the cecal cavity. During surgery, the appendix was found to be inverted completely into the cecum; ileocecal resection with regional lymph node dissection was performed. Microscopic examination revealed well-differentiated adenocarcinoma in tubular adenoma. Diagnosis of intussusception with carcinoma of the appendix is often difficult because appendiceal carcinoma with intussusception of the appendix is a rare condition. Although this condition can be diagnosed by radiographic imaging or colonoscopy, computed tomography has also been useful. The clinical manifestation of appendiceal intussusception with primary appendiceal tumor resembles a large cecal polyp, but its treatment differs greatly. Failure to recognize this condition may result in unexpected complications such as consequent peritonitis in case of endoscopic removal.