A rare case of metastatic follicular thyroid carcinoma of mandible

Abstract

Follicular thyroid carcinoma (FTC) is the second most common thyroid malignancy after papillary thyroid carcinoma (PTC) and very few cases have been reported with metastasis to the mandible as first clinical sign. Herein, we present a case of metastatic thyroid carcinoma of mandible in a middle-aged adult who presented with a mild diffuse swelling in the mandibular right buccal vestibular region. Radiology revealed destructive radiolucent lesion in the right body region of mandible. Microscopic examination revealed uncapsulated lesional tissue comprising of nests, follicles and trabeculae of tumor cells. Follicles were lined by cuboidal to low columnar cells enclosing eosinophilic colloid like material. Tumor cells were immunopositive for cytokeratin 7 and thyroid transcription factor-1 (TTF-1) and immunonegative for smooth muscle actin (SMA) and p40. Ki-67 proliferative index was 3 %. Based on the histological and immunohistochemical findings, diagnosis of metastatic follicular thyroid carcinoma was rendered.