Malignant transformation of ovarian mature cystic teratoma in a postmenopausal woman presented as acute abdomen.

Malignant transformation of mature cystic teratomas is uncommon but present in clinical practice. Especially in postmenopausal women, the clinical manifestation of a mature teratoma with undiagnosed malignant transformation as acute abdomen is extremely rare. In these cases, total hysterectomy with bilateral salpingo-oophorectomy is the treatment choice since the chance of malignancy is high.