PSAT326 Graves’ Thyrotoxicosis Resistant to Medical Therapy Found to Have Isolated Thyroid Sarcoidosis Without Systemic Involvement

Abstract

Abstract Background Sarcoidosis in thyroid gland is rare and is mostly reported in patients with systemic sarcoidosis. While thyroid hypofunction is the most common functional abnormality in thyroid sarcoidosis, concomitant Graves’ disease and sarcoidosis are reported. We describe a patient with Graves’ thyrotoxicosis resistant to anti-thyroid treatment requiring thyroidectomy and found to have thyroid sarcoid without evidence of systemic sarcoidosis. Case 31-year-old female presented with dysphagia, enlarged thyroid, heat intolerance, tremors, anxiety, palpitations and weight loss for two months. Laboratory testing demonstrated hyperthyroidism with positive TPO/TSI and hypercalcemia. She was diagnosed with Graves’ disease and started on anti-thyroid therapy (methimazole). Due to persistent symptoms and persistent hyperthyroidism, the dose was up-titrated. However, despite 1 year of high dose anti-thyroid therapy, she had persistent symptomatic hyperthyroidism and hypercalcemia. Due to concern for potentially fatal complications of uncontrolled hyperthyroidism and hypercalcemia, she underwent total thyroidectomy 1 year after her initial diagnosis. Her symptoms improved, thyroid function studies normalized, and hypercalcemia resolved. On histologic examination, the thyroid demonstrated diffuse hyperplasia compatible with Graves’ disease and non-caseating granulomas in thyroid interstitium and one perithyroidal lymph node in a distribution compatible with sarcoidosis. Grocott and acid-fast stains were negative for fungi and acid-fast organisms. An interferon γ release assay was negative for TB. Chest X ray and ACE level was normal suggesting no active sarcoid disease. After 1 year follow up, patient continues to have no signs of systemic sarcoidosis. Discussion We found four reported cases of patients with Graves and systemic sarcoidosis with uncontrolled thyrotoxicosis requiring thyroidectomy and found to have thyroid sarcoid 1,2,3. We found only one other case of isolated thyroid sarcoid causing hyperthyroidism without systemic sarcoidosis4. In patients with Grave's disease, sarcoidosis in thyroid gland may contribute to the resistance to antithyroid therapy and often require thyroidectomy. We continue to monitor our patient for signs of sarcoidosis.