Malignancy associated with ovarian teratomas: frequency, histotypes, and diagnostic accuracy of intraoperative consultation.

Mature cystic teratomas are common ovarian germ cell tumors that rarely undergo malignant transformation, and intraoperative consultation is generally not warranted. The aims of this study were to review a large number of ovarian teratomas (OTs), to document the rate and histotypes of associated malignancy, and to identify parameters that may be associated with malignancy. In this study, a retrospective medical record review of patients diagnosed as having OTs from 2002 to 2011 was performed. Patient age, tumor size, type, and laterality were obtained from pathology reports and operative notes. A total of 956 OTs that ranged in size from 0.3 to 45 cm were identified. Intraoperative consultation was requested in a total of 316 (33.1%) of 956. Intraoperative gross evaluation only was performed on 211 (66.8%) of 316, of which 4 cases were malignant on final diagnosis. Frozen section was performed on 105 (33.2%) of 316, of which 12 were malignant on final diagnosis. The final diagnoses of all OT cases were as follows: 26 (2.7%) of 956 were associated with malignant tumors. The latter were larger than benign cases (average sizes, 11.2 cm vs 6.5 cm; P < .001), and patients with malignant tumors were significantly older than those with benign mature cystic teratoma (48.7 years vs 38.8 years, P < .001). The sensitivity and positive predictive value of frozen section examination during the intraoperative consultation for the detection of malignancy in OTs are 80% and 100%, respectively. In conclusion, patient age and large tumor size were associated with malignancy in this data set. Mucinous and serous borderline tumors were more common than squamous cell carcinoma in our cohort.