A rare case of pseudomyxoma peritonei caused by borderline mucinous tumor arising from primary mature cystic ovarian teratoma

Pseudomyxoma peritonei (PMP) is a rare clinical syndrome characterized by diffuse intraperitoneal mucinous spread originating from mucinous neoplasms. The most common cause of PMP is a mucinous epithelial tumor of the appendix, but may also develop from other abdominal organs such as the ovaries, colon, and pancreas. Here, we describe the case of a patient with a prior history of appendectomy, in whom the appendix was easily excluded as the primary site of PMP. Previous studies have reported that only 3–8% of ovarian mucinous tumors may arise from mature cystic teratoma. In addition, borderline ovarian malignancies from mature cystic teratoma are not common, and the occurrence of PMPs from these borderline ovarian mucinous tumors is very rare. We report a rare case of PMP with clinicopathological features between PMP and borderline mucinous tumors arising in a mature cystic teratoma of the ovary.