Malignant transformation arising from mature cystic teratoma of the ovary: a report of six cases.

Aim: Malignant transformation of mature cystic teratoma (MCT) is an uncommon complication. Preoperative diagnosis is difficult because of the lack of specific symptoms and signs indicating malignancy. Thus, we retrospectively analyzed the clinical characteristics of patients and the role of surgery in their management.
Material and Methods: During a 9-year period (2002-2010), six patients with malignant transformation arising from ovarian MCT were treated at the Gynecologic Oncology Unit of Bakirkoy Woman and Children's Training and Research Hospital. A retrospective chart review and analysis of the patients' data were conducted.
Results: Malignant transformation arising from ovarian MCT accounted for 1.9% of all ovarian MCT (6/321). Three cases were stage IA and the other three were stage IC. Histologically, three of six cases had squamous cell carcinoma (50%), two had a carcinoid tumor (33%), and one had mucinous adenocarcinoma (17%). All patients underwent comprehensive surgical staging. Two patients received adjuvant chemotherapy and one received adjuvant chemoradiation. Five of six patients were observed for 16-104 months and no recurrence was detected. One patient with a carcinoid tumor in stage IC died of disease within 34 months following the surgery.
Conclusion: Early detection of malignant transformation arising from MCT is mandatory for treating patients, but in most patients malignancy was detected intraoperatively. Surgical cytoreduction with a complete staging procedure and adjuvant treatment may be reasonable for stage IC. Additionally, prognosis is better when the tumor is completely excised and does not extend beyond the capsule.
(© 2012 The Authors. Journal of Obstetrics and Gynaecology Research © 2012 Japan Society of Obstetrics and Gynecology.)