Appendiceal mucinous neoplasms (low-grade appendiceal mucinous neoplasm, high-grade appendiceal mucinous neoplasm, mucinous adenocarcinoma) can cause perforation, leading to extensive progression into the peritoneal cavity, deposition of both mucus and neoplastic cells, causing a syndrome clinically known as pseudomyxoma peritonei; accounts for more than 90% of pseudomyxoma peritonei origin.