Malignant teratoma of the thyroid in adult was first reported by Lurje in 1908, who described a case of a 53-yr-old woman (5
). By 1999, nineteen cases of malignant teratoma of the thyroid had been reported in the medical literature, emphasizing the aggressive clinical course of the disease (1
). After then, 3 cases have been reported (2
). There were a predominance of primitive neuroepithelial component within mature squamous or glandular epithelial components and mature cartilage in our case.
Malignant thyroid teratoma is an aggressive tumor, with a short median survival (median, 8 months) after surgery without postoperative chemotherapy. The commonly used drugs are the same agents effective in the treatment of germ cell tumors (6
). It usually consists of bleomycin, cisplatin, and etoposide (BEP) protocol alone or in combination with other agents aimed to treat the sarcomatous component. The most common agents included are vincristine, cyclophosphamide and actinomycin-D (2
Chen et al. reported a 32-yr-old woman with malignant thyroid teratoma who underwent a simple lobectomy of the thyroid (8
). She received chemotherapy of BEP and was still alive without evidence of disease after 6.7 yr. No further local radiotherapy or operation was arranged.
Djalilian, et al. reported a 33-yr-old woman with malignant thyroid teratoma who underwent 5 cycles of chemotherapy with vinblastin, ifosfamide, and cisplatin (1
). After 3 further cycles of carboplatin and etoposide, the patient underwent autologous bone marrow stem cell transplant. She did well with evidence of stable disease in the lungs at 21 months from the diagnosis but died of metastatic teratoma. Recently, high-dose chemotherapy in combination with autologous stem cell transplant has been found to be effective in prolonging the survival in some patients with gonadal germ cell tumors (10
Jayaram et al. treated a malignant teratoma of the thyroid with predominantly neuroepithelial differentiation with surgery alone (7
). She died after 15 months with metastases to liver, vertebra, paraaortic and paracaval lymph nodes.
Craver et al. reported a 15-yr-old black girl with a malignant thyroid teratoma with exuberant primitive neuroectodermal tumor components. There were bilateral nodal involvement and mediastinal extension (6
). She was treated with an aggressive combination chemotherapy of BEP and radiation. Further chemotherapy included vincristin, actinomycin-D, and cyclophosphamide alternating with ifosfamide and etoposide for six cycles. These agents were included to treat the sarcomatous component. Presently there is no residual disease 16 months after the diagnosis.
Kushner et al. treated 36 patients with poor-risk primitive neuroectodermal tumor (12
). The P6 protocol consists of high-dose cyclophosphamide, doxorubicin, and vincristine. The protocol achieved excellent pathological or clinical responses in 34 patients and partial responses in two patients. All six patients with metastatic disease limited to lungs achieved a complete response and did not relapse for the follow-up period of 7 to 36 months.
Primary thyroid malignant teratoma is rare. For teratomas of other sites with primitive neuroectodermal tumor components, the suggestion is to tailor the chemotherapy regimens known to be effective in the treatment of the transformed histology, after complete surgical resection (13
). Most of chemotherapeutic agents chosen for malignant teratomas of the thyroid have been selected and established for teratomas of other origins (10
). Therefore, we decided to administer an intensive chemotherapy regimen according to the NCI protocol INT-0091 (4
). Grier et al. compared the 49 weeks of standard chemotherapy consisting of doxorubicin, vincristine, cyclophosphamide and dactinomycin to chemotherapy alternating with ifosfamide and etoposide in primitive neuroectodermal tumor (Ewing's sarcoma) patients. They concluded that for nonmetastatic patients, the 5-yr disease free survival (69% vs. 54%) and overall survival (72% vs. 61%) were superior in the later group. We used the combination chemotherapy altering with ifosfamide and etoposide for this specific patient of primary malignant teratoma with a primitive neuroectodermal tumor component.
Some investigators have reported the role of EBRT for residual tumor tissues (5
). Although EBRT has frequently been used, its role in front-line therapy is not clear. Locoregional control at the time of recurrence seems to provide short-term palliation. We opted for the radiation treatment in this patient in light of the extensiveness of the disease and the residual microscopic disease after the surgery.
It is suggested that patients with primary malignant teratoma of the thyroid should be managed according to their major malignant component. The complete surgical excision and extensive chemotherapy are recommended for most patients with primary malignant teratoma (1
). As for the exuberant primitive neuroectodermal tumor component in this particular case with an extensive involvement of the surrounding soft tissue and lymph nodes, best clinical outcome could be obtained with intensive multidisciplinary therapies consisting of complete excision, chemotherapy and radiation therapy to the lesion.