A Rare Incidence of Metastatic Papillary Thyroid Carcinoma to the Mandible: A Case Report and Review of Literature

Papillary Thyroid Carcinoma (PTC) primarily metastasizes via regional lymphatics making its spread to the oral cavity exceedingly rare. Although this disease remains the most common endocrine malignancy, comprising roughly 85%-90% of all thyroid cancers, it’s occurrence within the oral cavity is seldom seen. This study identifies a case report involving a 77-year-old male with a past medical history of well-differentiated PTC that was initially treated with a total thyroidectomy and adjuvant radioactive iodine. Approximately five years after his initial treatment, surveillance imaging demonstrated a 3.0 x 1.8 x 2.0 cm expansile mass at the left mandibular body with erosion of the lingual cortex. An incisional biopsy then confirmed the diagnosis of metastatic papillary thyroid carcinoma. The patient was treated with a segmental resection of his mandible and final reconstruction utilizing a fibula free flap. Given the limited number of cases involving metastatic spread of PTC to the head and neck region, a standardized treatment algorithm does not currently exist. Thus, this case serves to provide a documented report of this rare occurrence and to review literature that may help other clinicians treat patients with this malignancy type. There remains a need for future studies to create risk stratification models for patients with metastatic PTC that consider margin analysis, genetic characteristics, and elevated risk factors for metastasis to tailor individual treatment plans.