Tehran University of Medical Sciences Journal of Family and Reproductive Health 1735-8949 17 4 2023 12 01 264 268 EN Maliheh Arab Department of Gynecology Oncology, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran Azadeh Jafari Ashtiani Department of Obstetrician and Gynecologist, Shahid Beheshti University of Medical Sciences, Tehran, Iran Nafiseh Faghih Department of Obstetrician and Gynecologist, Shahid Beheshti University of Medical Sciences, Tehran, Iran Behnaz Ghavami Department of Obstetrics and Gynecology, Tehran University of Medical Sciences, Tehran, Iran Behnaz Nouri Department of Obstetrician and Gynecologist, Shahid Beheshti University of Medical Sciences, Tehran, Iran Shahla Noori Ardabili Department of Obstetrics and Gynecology, Atieh Hospital, Tehran, Iran 2023 10 21 2023 11 25 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 https://jfrh.tums.ac.ir/index.php/jfrh/article/view/2509 https://jfrh.tums.ac.ir/index.php/jfrh/article/download/2509/664