A Case of Maxillary Malignant Ameloblastoma With Cervical Lymph Node Metastases of Thyroid Cancer

• Statements of the problem. We report a case of malignant ameloblastoma with cervical lymph node metastases of thyroid cancer.
•  Materials and methods. A 61-year-old male who had a swelling in his left maxillary and had visited a nearby dental clinic one month before, was referred to our hospital with the initial diagnosis of an ulcer in the left maxillary gingiva. Our preoperative diagnosis was maxillary malignant tumor. The patient had been suffering from mild diabetes and high blood pressure, and had been taking oral medicine to control these conditions.
• Method of data analysis.Two biopsy procedures revealed that the lesion was a malignant tumor. Though the histological type was not identified, adenosquamous cell carcinoma or odontogenic malignant tumor was suspected. We diagnosed it as a maxillary malignant tumor T4N1MO stage IVA.Preoperative selective intra-arterial chemotherapy and radiation therapy were conducted twice for the maxillary tumor. 40mg/body of docetaxel and 100mg/body of cisplatin were given through arteria femoralis respectively by means of the Seldinger method. Radiation therapy of 50Gy was also conducted.Diagnostic imaging showed a lymph node metastases in the cervical region. Since the histological type was not identified, cervical dissection was conducted. Cervical lymph node metastases of thyroid cancer was found in one of 32 submandibular lymph nodes. After conducting preoperative selective intra-arterial chemoradiotherapy, an operation was conducted to resect the malignant tumor in the maxillary under general anesthesia. Incision was conducted along the Weber’s incision line. The left maxillary bone was resected completely while the inferior wall of the orbit was preserved, and split-thickness skin grafting was conducted. Pathological analysis revealed malignant ameloblastoma. A gastric fistula was made for nutritional care during the treatment.
• Results of investigation.Although it was difficult to identify the histological type of the tumor by pathological analysis, squamous cell carcinoma, ameloblastoma carcinoma, adenoid cystic carcinoma or malignant ameloblastoma was suspected. Thyroid cancer (papillocarcinoma) was found in one of 32 accessory nerve lymph nodes through cervical dissection. Immunostaining showed a positive reaction to thyrogloblin and TTF-1. Reexamination of the biopsy lesion revealed that the tumor was infiltrating and increasing in number, while forming alveolar configurations. Comedo-like necrotic focuses were observed in the inside of some alveolar configurations. The tumor cells showed a high N/C ratio and looked like basal cells. The peripheral region of the cancer cell nest contained the palisade arrangement of nuclei. Since the tumor in the maxillary was positive for CK5/6 and CD56 and negative for P63, syanptophysin and chromogranin-A in immunostaining, we concluded that it was a malignant ameloblastoma.
• Conclusions relevant to the problem.The patient has had no recurrence of carcinoma in the maxillary during the four years after the operation. He has undergone examination of the maxillary every two months. Although artificial teeth are used for the resected part in the maxillary, there is no problem with regard to dietary intake, pronunciation or appearance. The thyroid gland cancer has been checked by means of MRI, CT, and US as well as a tumor marker (thyroglobulin). Since no solid lesion has been found in imaging and the tumor marker remains at a normal level, the case has been followed up without resection of the thyroid gland. Ultrasonography of the cervical region and thyroid gland as well as tumor marker examination have been conducted as follow-up every six months.
• list of two references.1) Dhir K, et al: Ameloblastic carcinoma of the maxilla. Oral Oncology 39: 736-741, 2003  2) Yasuhisa Tomaru et al: Application of thermoradiotherapy to the case of advanced malignant ameloblastoma. Journal of the Japanese Society of Oral and Maxillofacial Surgeons 43: 185-187, 1997