RESUMO
Objective: Malignant transformation in dermoid cysts is rare, and Squamous Cell Carcinoma (SCC) is the most common form. This event often occurs in large tumors and middle-aged women. Case report: In this study, two cases are presented. They were menopause, and abdominal pain and adnexal mass was a common manifestation in both. Case 1 with adenocarcinoma arising in mature cystic teratoma had abnormal tumor markers and was diagnosed with a frozen section during surgery, but case 2 with SCC transformation had normal tumor markers, and the frozen section was not helpful in the first surgery. Both underwent complete staging surgery, and due to stage IC1 in case 1, she received chemotherapy, and in case 2, no adjuvant treatment was needed because of stage IA. Conclusion: Considering the rarity of malignant transformation in the dermoid cyst, the best surgical approach and adjuvant therapy indications need further research.