Malignant Thyroid Teratoma

ABSTRACT Objective: Malignant teratomas of the thyroid are very rare, with less than 30 cases reported in adults. Presentation of a recent patient and a review of the literature have provided insight into the usual clinical presentation and histopathologic characteristics of malignant teratomas of the thyroid gland in adults and the available management options for this disease process. Methods: A healthy 33-year-old woman presented with a rapidly growing right neck mass. Fine-needle aspiration demonstrated poorly differentiated carcinoma favoring thyroid origin. The patient underwent total thyroidectomy, bilateral central compartment neck dissection, and right lateral neck dissection. Histopathologic analysis confirmed the diagnosis of malignant teratoma of the thyroid gland with metastases to the neck bilaterally. Results: Malignant teratomas are exceedingly rare tumors of the thyroid gland. These masses are typically diagnosed after thyroidectomy by histopathologic criteria. Fine-needle biopsy generally does not allow for sufficient sampling of the tumor. Historically, malignant thyroid teratoma has a poor prognosis. No standard treatment protocol has been widely accepted given the rarity of the disease, but surgical excision is recommended, followed by radiation and/or chemotherapy. Length of survival from this disease has increased since earlier reported cases, possibly due to a trend towards more aggressive adjuvant treatment in recent years. Conclusion: Malignant thyroid teratoma is a rare and aggressive disease process that requires multimodal treatment. Abbreviations: BEP = bleomycin, etoposide, and cisplatin; MTT = malignant thyroid teratoma