“…The frequency of malignant transformation is about 1%, and the most common type of malignant transformation is that to squamous cell carcinoma [ 2 , 3 , 4 ]. Malignant melanoma, primary osteosarcoma, dedifferentiated chondrosarcoma, rhabdomyosarcoma, and angiosarcoma arising in dermoid cysts have been reported in the literature [ 5 , 6 , 7 , 8 , 9 ]. A malignant fibrous histiocytoma developing in a mature cystic teratoma is extremely rare; to the best of our knowledge, only eight such cases have been previously reported.…”