Mucinous adenocarcinoma arising in ovarian mature cystic teratoma in pregnancy.

We report a case of mucinous adenocarcinoma arising from mature cystic teratoma (MCT) of the ovary ascertained incidentally during pregnancy. An ovarian adnexal mass was seen in a 38-year-old pregnant woman during cesarean section. Oophorectomy revealed a mucinous adenocarcinoma arising from MCT with additional capsule invasion. Following this, staging procedures were applied. The patient was staged as IC and adjuvant chemotherapy was applied. She has remained disease-free for over 24 months. To our knowledge, this is a case of mucinous adenocarcinoma arising from MCT and the third case of malignant transformation from MCT in pregnancy in English literature.