Confined Low Grade Appendiceal Mucinous Neoplasm With Coexisting Distant Metastasis

Appendiceal mucinous neoplasms (AMNs) are tumors with dysplastic mucinous epithelium, a pushing growth pattern but no infiltrative invasion to the appendiceal wall. Some AMNs are associated with pseudomyxoma peritonei, characterized by intraperitoneal mucinous involvement. Recent studies have demonstrated that LAMNs confined to the appendix have low or no risk for disease recurrence, progression, and peritoneal involvement during follow up.

Here, we present two extremely rare cases with confined low grade appendiceal mucinous neoplasm (pTis and pT3) and simultaneous extraperitoneal subcutaneous or ovary involvement at the time of diagnosis.

Our cases demonstrate that although the primary tumor is limited to the appendix, coexisting distant metastasis may occur on very rare occasions.