PSAT296 Graves’ Disease and Hurthle Cell Carcinoma: A Rare Presentation

INTRODUCTION: Hurthle cell carcinoma is a rare thyroid malignancy, only accounting for 3-5% of all thyroid malignancies. Thyroid tumors are classified as Hurthle cell carcinomas when they contain more than 75% Hurthle cells. Hurthle cells are oncocytic cells with an acidic cytoplasm and can contain up to 5,000 mitochondria. In the thyroid, oncocytic changes are associated with conditions such as cell-mediated autoimmune thyroiditis, humoral-mediated hyperthyroidism (Graves’ disease), and hyperplastic nodules seen in multinodular goiters. CASE PRESENTATION: A 64-year-old Polish female with a medical history of hypertension, hyperlipidemia, and smoking presented with fatigue, weight loss of 18kg in 6 months, palpitations, tremors, anxiety, heat intolerance, and diarrhea. Family history was pertinent for thyroid lobectomy in older sister and thyroidectomy in niece with reportedly benign pathology. She denied any family history of thyroid cancer. She resided 1,000 kilometers away from Chernobyl at the time of the nuclear accident. DIAGNOSIS AND TREATMENT: Hyperthyroidism was attributed to Graves’ disease, and she was started on methimazole with improvement in symptoms. Fine needle aspiration of 3.4cm right thyroid nodule showed moderate to high cellularity with abundant discohesive Hurthle cells with granular cytoplasm, large nuclei with prominent nucleoli and mild nuclear atypia consistent with Hurthle cell carcinoma with a 25-40% risk of malignancy. She had a total thyroidectomy that revealed a 3cm minimally invasive Hurthle cell carcinoma with a benign lymph node. She was started on levothyroxine 100mcg. Post-surgery labs showed thyroglobulin 3 ng/mL [1.3-31.8], undetectable thyroglobulin antibody, suppressed TSH and normal calcium levels. Further course was complicated by Graves’ orbitopathy, worsened by smoking. She was started on teprotumumab and tapered dexamethasone before receiving 30 mCi radioactive iodine for remnant ablation. DISCUSSION AND CONCLUSION: Graves’ disease is the most common cause of hyperthyroidism accounting for 60%- 80% of hyperthyroid cases. Graves’ disease has been reported to be associated with aggressive thyroid carcinomas, 88%being papillary thyroid cancers. Some studies note an increased mortality in patients with differentiated thyroid cancer associated with Graves’ disease when compared to euthyroid controls. Hurthle cell carcinoma is a rare thyroid malignancy and is uncommonly seen in conjunction with Graves’ disease. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.