Follicular thyroid carcinoma metastasis to the facial skeleton: a systematic review

BACKGROUND: Follicular thyroid carcinoma (FTC) metastasis to the facial skeleton is exceedingly rare. A case of FTC metastasizing to the mandible is presented and a systematic review of the literature describing thyroid metastasis to the facial skeleton is performed. CASE PRESENTATION: A 73-year-old female presented with metastatic FTC to the mandible and underwent total thyroidectomy, segmental mandibulectomy, bone impacted fibular free flap reconstruction, and adjuvant radioactive iodine treatment. The PubMed database was searched for literature describing thyroid cancer with facial skeleton metastasis using the key words “thyroid,” “cancer,” “carcinoma,” “metastasis,” and “malignancy” with “oral cavity,” “maxilla,” “mandible,” “sinus,” “paranasal,” and “orbit.” Reports that only involved the soft tissues were excluded. Systematic review revealed 59 cases of well-differentiated thyroid cancer with facial skeleton metastasis: 35 mandibular metastases (21 = FTC), 6 maxilla metastases (2 = FTC), 9 orbital metastases (4 = FTC), and 11 paranasal sinus metastases (7 = FTC). Treatment included surgery, RAI, external beam radiotherapy (XRT), or a combination of these modalities. The one, two, and five-year survival rates were 100%, 79%, and 16%, respectively. CONCLUSION: Facial skeleton metastasis of FTC is a rare clinical challenge. Optimal treatment appears to include total thyroidectomy and resection of involved structures with or without adjuvant treatment.