Clinical experience in ovarian squamous cell carcinoma arising from mature cystic teratoma: A rare entity

OBJECTIVE: We sought to investigate the clinicopathologic features of ovarian squamous cell carcinomas arising from mature cystic teratomas (MCT) and to report our clinical experience and lessons learned. METHODS: From January 1993 to November 2012, a total of 6,260 women with ovarian MCT were surgically treated at Cheil General Hospital and Women's Healthcare Center. Among them, the cases with malignant transformation to squamous cell carcinoma were included in this analysis. Patient demographic characteristics, surgical findings, and prognosis were evaluated retrospectively. RESULTS: Of the 6,260 ovarian MCT patients, four (0.06%) had ovarian squamous cell carcinoma arising from MCT. The mean patient age was 43 years (range, 35-51 years), and the mean tumor size was 12 cm (range, 9-16 cm), with two patients in the International Federation of Gynecology and Obstetrics stage I and the other two in stage III. Upon preoperative imaging, all cases were expected to be benign ovarian tumors, but the preoperative squamous cell carcinoma antigen level was elevated from 1.5 ng/mL in stage Ia to 11.3 ng/mL in stage IIIc, suggesting malignancy, while the CA-125 level was normal in two of the three patients who received the test. Optimal debulking surgery was performed and adjuvant chemotherapy was used in all patients, but death from the recurrence of disease occurred in one patient, whose overall survival was 10 months. CONCLUSION: Ovarian squamous cell carcinoma arising from MCT is extremely rare, and it is rarely diagnosed preoperatively on imaging workups. Measuring the squamous cell carcinoma antigen level might be a useful diagnostic clue, and it might also be predictive of the tumor stage. An adequate staging surgery should be included in the standard treatment, but multicenter studies are needed to confirm this.