A rare case of squamous cell carcinoma arising in a mature cystic teratoma of the ovary.

Mature cystic teratoma is a common benign adnexal tumor in females. We describe a 43-year-old female with a 10 cm left ovarian mature cystic teratoma with the rare finding of squamous cell carcinoma. The clinical evaluation with ultrasound and serologic markers is discussed. Treatment typically consists of surgical resection with adjuvant chemotherapy using platinum-based agents. Prognosis is extremely poor in most cases.