Vermiform appendix torsion is rare, and even more uncommon is the volvulus of appendiceal mucinous tumors. To our knowledge, only nine cases of torsion of the vermiform appendix associated with appendiceal mucinous neoplasms have been reported up to date. We report a case of secondary torsion of the vermiform appendix with mucinous cystadenoma in a 30-year-old man. The symptoms were consistent with acute appendicitis. Diagnostic laparoscopy revealed a mucinous tumor of the appendix with a 360 degrees twisted appendix. In order to avoid peritoneal dissemination open appendectomy was performed. The final pathologic diagnosis was a mucinous cystadenoma of the appendix. The postoperative recovery was uneventful. Secondary torsion of vermiform appendix with mucinous cystadenoma is a rare entity. Correct preoperative diagnosis is unlikely. Open appendectomy is the standard of care for benign mucinous appendiceal tumors. Furthermore, it is important to prevent spillage of the appendiceal mucocele content.