Primary Malignant Thyroid Teratoma: An Institutional Experience

Background: Primary malignant thyroid teratomas are very rare tumors (fewer than 35 previously reported cases in the literature) typically affecting young adult women. While prognosis is poor, there have been some reports of successful treatment regimens. Four cases treated successfully are reported, and a review of the existing literature is provided. Patient findings: Medical records of four patients with histopathologically confirmed malignant thyroid teratomas treated at the University of Texas MD Anderson Cancer Center between 1994 and 2017 were reviewed. The patients were treated with variable treatment regimens consisting of surgical excision with or without aggressive combination chemotherapy (bleomycin, etoposide, and cisplatin; cyclophasphamide, adriamycin, and cisplatin; actinomycin-D, cyclophosphamide, and etoposide; bleomycin, vincristine, and cisplatin; or vincristine, methotrexate, bleomycin, and cisplatin). Summary: All four patients were young women <40 years of age. One patient had thyroid surgery alone, another had surgery with postoperative adjuvant chemotherapy, and two patients underwent neoadjuvant chemotherapy with significant tumor regression prior to definitive thyroid surgery. No patients had postoperative radiation therapy. All patients remained alive and disease free a median of 172 months (range 52-282 months) following completion of therapy. Conclusions: This case series represents the largest and longest follow-up from a single institution in the literature to date on primary malignant thyroid teratomas. Based on the existing literature and the authors' experience with these four patients, it is suggested that neoadjuvant chemotherapy combined with surgical excision is a promising approach for patients with gross extrathyroidal extension, cervical lymph node metastases, and/or distantly metastatic disease.