Squamous cell carcinoma arising in an ovarian mature cystic teratoma

Malignant transformation in a mature cystic teratoma of the ovary is rare. We describe a case of advanced-stage squamous cell carcinoma arising from a mature cystic teratoma in a 63-year-old postmenopausal woman. The initial investigation by ultrasound showed a left adnexal mass with mixed echo pattern, which arose the suspension of malignancy. She underwent a hysterectomy with left salpingo-oophorectomy for the removal of ovarian cyst. Histopathology was compatible with well-differentiated squamous cell carcinoma arising in a mature cystic teratoma. The tumor was invading the fallopian tube as well as serosa and myometrium of the uterus. Subsequently, she underwent two courses of combination chemotherapy with cisplatin, leucovorin, and 5-fluorouracil with no response. She died from progression of the disease, within 1 year after the initial operation.