Mandibular osteoblastic metastasis of poorly differentiated carcinoma of the thyroid gland

Metastasis of malignant tumors to the oral cavity is rare. The authors report a case of thyroid carcinoma with mandibular osteoblastic metastasis. An 83-year-old female presented with lower jaw swelling and pain. An elastic hard subcutaneous mass was observed in the median mandible. X-ray images confirmed a tumor lesion with periosteal reaction spreading radially from the mandible. A biopsy revealed nests of large, polygonal tumor cells growing in a supporting fibrovascular framework. The patient's anamnesis included thyroid carcinoma with lung metastasis, 2 years ago, treated by total enucleation of the thyroid and excision of the superior lobe of the left lung. Biopsy, primary and metastatic tumor samples all tested positive for thyroglobulin, suggesting a thyroid follicular epithelial origin. Mandibular metastasis of poorly differentiated carcinoma of the thyroid gland was diagnosed. Consent for further treatment was not obtained. The patient died 1 year and 7 months later.