De novo thyroid-associated ophthalmopathy diagnosed after total thyroidectomy for papillary thyroid carcinoma: A case report

We report an extremely rare case of thyroid-associated ophthalmopathy (TAO) that developed 9 years after total thyroidectomy for papillary thyroid carcinoma (PTC). A non-smoking 65-year-old woman received radioactive iodine (RAI) ablation (131I 50 mCi) after total thyroidectomy and a post-RAI whole-body scan revealed accumulation of radioiodine in the left thyroid bed. Computed tomography (CT) showed radioiodine-negative lung metastases. Subsequently, she underwent additional RAI treatment (131I 100 mCi). Approximately 9 years after the total thyroidectomy, diplopia, proptosis of the right eye, and oculomotor abnormalities appeared. T2-weighted fat-suppression images of orbital magnetic resonance imaging (MRI) showed a high signal intensity area and swelling in the inferior rectus muscle of the right eye, and laboratory tests showed high thyroid-stimulating hormone receptor antibody (TRAb) and thyroid-stimulating antibody (TSAb) levels, leading to the diagnosis of TAO. Triamcinolone acetonide (40 mg) was injected twice in the vicinity of the right inferior rectus muscle. Posttreatment orbital MRI showed improvement in inflammation and swelling of the inferior rectus muscle of the right eye; however, limited elevation of the right eye persisted. Having encountered this valuable case, it is crucial for clinicians to be aware that TAO can develop even after surgery for thyroid cancers.