Follicular thyroid carcinoma presenting as bilateral cheek masses

Mandibular metastasis of thyroid carcinoma is extremely rare. We present the case of a 46-year-old woman who had bilateral huge cheek masses that had grown rapidly over several years. Intra-oral mucosal tissue biopsy and imaging work-up including computed tomography scan and magnetic resonance imaging were performed and the initial diagnosis was presumed to be central giant cell granuloma. Incidentally detected thyroid lesions were studied with ultra-sonography guided fine needle aspiration and diagnosed as simple benign nodules. Due to continuous oral bleeding and the locally destructive feature of the lesions, we decided to excise the mass surgically. To avoid functional deficit, a stepwise approach was performed: Firstly, the larger left mass was excised and the mandible was reconstructed with a fibular free flap. The final pathologic diagnosis was follicular thyroid cancer. Postoperative I-131 thyroid scan and whole body positron-emissions-tomography were performed. Right side mass was revealed as a thyroid malignancy. Multiple bony metastases were detected. Since further radioactive iodine therapy was required, additional total thyroidectomy and right side mandibulectomy with fibular free flap reconstruction was performed. The patient also underwent high dose radioactive iodine therapy and palliative extra-beam radiotherapy for the metastatic lumbar lesion. Follicular thyroid carcinoma should be considered as a differential diagnosis for mandibular mass lesions.