The most frequent ovarian germ cell tumors are mature cystic teratomas (MCTs), composing 10-25% of all ovarian neoplasms. MCTs have the potential of undergoing malignant transformation, typically in postmenopausal women, with a frequency of 0.17-3%, with squamous cell carcinoma being the most common malignant tumor arising from MCT. We present the rare clinical entity of a squamous cell carcinoma arising from a mature cystic teratoma in a 56-year-old premenopausal woman as well as diagnostic and therapeutic route followed.