Computed tomography diagnosis of primary thyroid teratoma.

Teratomas occur mainly in the gonads, and rarely in the thyroid. They are common in reproductive age women. Teratomas in the thyroid occur mainly in neonates and are often benign. Here we report a case of primary benign teratoma of the thyroid gland in a 15-year-old female, which was accurately diagnosed by computed tomography before surgery. The tumor was a well-defined cystic mass in the right thyroid region, with a fat-containing nodule in the cystic tumor causing displacement of the trachea. The patient was treated with right subtotal thyroidectomy and no recurrence was noted during 2 years' follow-up. Demonstration of the fat component within a well-defined cystic mass in the thyroid region allows accurate diagnosis of teratoma, localization of the tumor extent before operation, and adequate treatment.