Papillary Carcinoma Arising from Ectopic Thyroid Tissue in the Spinal Cord

Abstract

Ectopically located thyroid tissue is uncommon and if present, is usually found in the lateral neck. Rarely, this may give rise to a carcinoma. The diagnosis rests on post-surgical histopathologic examination. We present a rare case of papillary carcinoma arising from ectopic thyroid tissue in the spinal cord in a 12-year old girl who developed spinal cord compression T4 level in 2004. She underwent laminectomy with tumor excision and histopathologic diagnosis was ependymoma. The spinal cord mass recurred when she was 17 years old (in 2009) and the tumor was excised. Tissue staining with thyroglobulin, thyroid transcription factor-1 (TTF-1) and epithelial membrane antigen (EMA) were positive. Pathologic diagnosis was papillary carcinoma. Subsequently, she underwent a total thyroidectomy to confirm an occult primary thyroid cancer; however, histopathologic examination of the thyroid was benign. Whole body scan using I-131 did not reveal extrathyroidal uptake. Radioactive iodine ablation was not done. She was maintained on a suppressive dose of levothyroxine. She remained paraplegic, with no evidence of tumor recurrence two years since her last surgery.