Presentation of right lower quadrant pain with atypical findings

We present a 57-year old male patient with symptoms of an acute appendicitis. Surprisingly, preoperative sonography revealed an atypical cystic mass in the right lower quadrant of the abdomen with signs of sedimentation. Laparoscopy showed a ruptured appendiceal mucocele with peritoneal adherent mucus. The patient was treated with ileocecal resection. Histopathological examination revealed an infiltrating mucinous cystadenocarcinoma of the appendix. The patient will be treated with adjuvant intraperitoneal chemotherapy. Despite typical clinical signs of appendicitis a sonographically atypical cystic mass in the right lower abdomen should raise suspicion of a mucocele, eventually on the base of a neoplasm.