Papillary Thyroid Carcinoma Metastasis to the Epidural Space: A Case Report and Literature Review.

Papillary thyroid carcinoma is the most common thyroid cancer and commonly presents asymptomatically in a patient with cervical node enlargement. The defining characteristic of metastatic papillary thyroid carcinoma is its ability to spread through the lymphatic system. However, this case details a 71-year-old woman with metastatic papillary thyroid carcinoma who presents initially with complaints of back pain and leg weakness. Imaging showed an epidural mass with a pathologic fracture at the 10th thoracic vertebrae (T10). A T10 corpectomy with tumor excision and posterior T8-L1 laminectomy with fusion was performed, and the patient's pathology report returned as a follicular variant of papillary thyroid carcinoma. The patient underwent a total thyroidectomy three months later. The literature review of similar cases was limited due to the rarity of this presentation, and our search returned only three previously reported cases of papillary thyroid carcinoma metastasizing to the epidural spine. Limited prognostic factors, including age and metastasis site, were found, which may be relevant to our patient's outcomes. This case highlights the unique metastatic behavior of the follicular variant of papillary thyroid carcinoma and underscores its importance in expanding the current understanding of rare metastatic presentations. Furthermore, this case emphasizes the need for vigilance in diagnosing spinal metastases in patients with atypical presentations and demonstrates the importance of multidisciplinary management to achieve the best long-term outcomes.