[Appendiceal tumors found at appendectomy]

There are three main histologic types of appendiceal tumor: adenoma, adenocarcinoma, and neuroendocrine tumor. Neuroendocrine tumors (carcinoids) are by far the most common and account for two-third of all appendiceal tumors. Adenomas and adenocarcinomas are both rare; they share two particularities: (a) a mucinous component is both frequent and predominant, (b) they have a tendency to intraperitoneal dissemination. Rupture of any mucinous tumor-whether spontaneous or occurring during surgery-may result in pseudomyxoma peritonei; treatment of this condition requires complete resection of all lesions followed by hyperthermic intraperitoneal chemotherapy. For unruptured appendiceal tumor, the appendix should be removed by a carcinologic right hemicolectomy if the tumor appears aggressive.