Endocrine Abstracts

Introduction: Spinal metastasis is a common complication of many cancers, but it is rare for asymptomatic thyroid malignancies to present as paraplegia. Follicular thyroid carcinoma (FTC) metastasizes to bone in 7% to 28% of cases. While distant metastases often indicate poor prognosis, differentiated thyroid cancer (DTC) can sometimes lead to favourable outcomes.

Case Report: A 71-year-old man presented with a six-week history of thoracic back pain that progressed to bilateral leg weakness, without sensory loss or bowel/bladder dysfunction. He had no history of trauma or known thyroid disease. Examination revealed reduced lower limb power, particularly on the right, with hyperreflexia Blood tests, including Vitamin B12 and folate, were normal. An elevated paraprotein led to a myeloma evaluation, which was ruled out by a bone marrow biopsy. MRI showed a malignant compression fracture at the T9 vertebra with canal stenosis and spinal cord compression. High-dose corticosteroids were initiated, followed by immediate neurosurgical decompression. Histopathology confirmed infiltration by an epithelioid neoplasm positive for TTF1 and thyroglobulin, confirming metastatic carcinoma of thyroid origin. Although thyroid examination and tests were normal, ultrasound revealed a 17-mm nodule in the right lobe with calcification and a hypoechoic area (U4). Fine-needle aspiration revealed a follicular-patterned lesion (Thy3F), positive for TTF-1 and PAX8, which correlated with spinal metastasis histology. After discussion in the multidisciplinary meeting, a plan was made for a total thyroidectomy followed by adjuvant radioactive iodine (RAI) treatment.

Conclusion: It is highly uncommon for differentiated thyroid cancer to manifest as spinal cord compression as initial presentation. This case underscores the importance of including thyroid carcinoma in the differential diagnosis for patients presenting with unexplained spinal lesion. Quick identification and a comprehensive treatment approach involving various specialists are crucial for achieving the best results for the patient and ensuring positive outcomes.