Background: Intramedullary spinal cord metastasis (ISCM) from papillary thyroid carcinoma (PTC) is extremely rare and poorly documented. In this article, a case of lumbar ISCM from PTC is presented.

Case Presentation: A 55-year-old woman presented with persistent back pain. An intramedullary mass was found at the L1 level. Although there was no known thyroid disease, the pathology result was PTC metastasis. Subsequent thyroid ultrasound and biopsy confirmed the diagnosis. She also underwent a thyroid operation and radioiodine treatment. Although sensory deficits persisted, the patient's back pain improved.

Conclusion: Spinal metastases are an unusual presentation of PTC. This case highlights the importance of multidisciplinary management of ISCM from PTC, focusing on surgical intervention to improve outcomes.