Preoperative Diagnosis and Surgical Approach of Appendiceal Mucinous Cystadenoma: Usefulness of Volcano Sign.

We report a case of appendiceal mucinous cystadenoma that was successfully diagnosed preoperatively and treated by laparoscopic resection. We could find volcano sign on colonoscopy and cystic lesion without any nodules at the appendix on computed tomography (CT). Without any malignant factors in preoperative examinations, we performed laparoscopic appendectomy including the cecal wall. We could avoid performing excessive operation for cystadenoma with accurate preoperative diagnosis and intraoperative finding and pathological diagnosis during surgery. Appendiceal mucocele is a rare disease that is divided into 3 pathological types: hyperplasia, cystadenoma, and cystadenocarcinoma. The surgical approaches for it remain controversial and oversurgery is sometimes done for benign tumor, because preoperative diagnosis is difficult and rupturing an appendiceal tumor results in dissemination. Based on our study, volcano sign on colonoscopy and CT findings were important for the preoperative diagnosis of appendiceal mucocele. Furthermore, we think that laparoscopic resection will become a surgical option for the treatment of appendiceal mucocele.