Malignant transformation of mature cystic teratoma of the ovary: a case series.

OBJECTIVE: The aim of this study was to analyze the patients with malignant transformation (MT) arising in mature cystic teratoma of the ovary (MCTO) and evaluate the clinicopathologic features, managements, and prognosis of these cases. The records of the patients with MT arising in MCTO who were treated at our hospital were reviewed retrospectively. The demographic features, presenting symptoms, preoperative ultrasonographic evaluations, surgical treatments, pathological findings, adjuvant therapies, follow-up outcomes, and survival time were examined. Eighteen patients with MT arising in MCTO were detected during the study period. The incidence rate of MT was 0.404% of all MCTO and squamous cell carcinoma was the most common histologic type (66.7%). The median age of the patients was 48 (range, 28-79) and the mean tumor size was 12 cm. Eleven patients (61.1%) were classified as stage IA, 1 (5.6%) as stage IC, 1 (5.6%) as stage IIC, 4 (22.2%) as stage IIIC, and the remaining 1 (5.6%) as stage IV. The overall 5-year survival rate was 66.7%. MT of MCTO is a rare occurrence entity and early detection and complete surgical staging are cardinal for survival. Additionally, this malignancy usually occurs in postmenopausal women and the high tumor diameter may be associated with MT.