Development of Graves orbitopathy after thyroidectomy for thyroid cancer.

We present a case of a 76-year-old female with a history of papillary thyroid cancer treated with a total thyroidectomy, central neck dissection, and radioactive iodine (RAI) in 2006. Sixteen years later, she was found to have lung metastases and underwent a treatment dose of RAI. Given no improvement in her thyroglobulin levels, she underwent a third dose of RAI. One week following this, she presented with new ophthalmalgia, conjunctival injection, and binocular diagonal diplopia. She was diagnosed with a complex ophthalmoplegia, and a magnetic resonance imaging scan of her orbits revealed symmetric bilateral exophthalmos and bilateral enlargement of her extraocular muscles suggesting Graves ophthalmopathy. Her TSH receptor antibody was elevated at 10.1 IU/L (reference range, <1.8 IU/L), consistent with de novo Graves disease. We highlight the possibility that an overflow of TSH-receptor antigens following RAI treatment in patients with metastatic thyroid cancer can lead to the formation of TSH-receptor antibodies, presenting as Graves ophthalmopathy many years following total thyroidectomy.