MON-400 From Hyperplasia to Malignancy: The Dual Face of Graves’ Disease

Abstract Disclosure: N. Sweis: None. Y. Velis: None. J. Sanchez Perez: None. Introduction: The coexistence of papillary thyroid carcinoma (PTC) and Graves’ disease (GD) presents unique diagnostic and therapeutic challenges. Thyroid nodules in GD patients require careful evaluation, as hyperthyroidism can obscure malignancy risks. This case highlights a patient with GD and PTC, with the diagnosis confirmed after thyroidectomy. Case presentation: A 57-year-old female with a history of GD diagnosed in 2022, characterized by an initial TSH of <0.005 mIU/L (reference range: 0.270-4.200 mIU/L), free T4 of 2.94 ng/dL (reference range: 0.82-1.77 ng/dL), and a positive thyroid-stimulating immunoglobulin (TSI) of 262 (normal <140% baseline), currently managed with methimazole, presented for evaluation of a thyroid nodule. A thyroid ultrasound performed in 2024 revealed multiple nodules, including one in the right thyroid lobe for which fine-needle aspiration (FNA) was recommended. The FNA findings were suspicious for papillary thyroid carcinoma, which was subsequently confirmed on pathology following thyroidectomy. Discussion: While thyroid nodules in hyperthyroid patients are often treated similarly to those in euthyroid individuals, autoimmune inflammation and TSIs may influence nodule development and malignancy risk. The literarture suggests that the malignancy rate for thyroid nodules in patients with GD typically ranges from 2% to 17%, with some studies reporting a rate as high as 45.8%, with the average reported rate being 16.9%.1-2 This is notably higher than the roughly 5% malignancy rate observed in thyroid nodules within the general population. Contrast this with "hot nodules," which are autonomously functioning and have a low risk of cancer; these do not typically require biopsy. However, nodules in the setting of GD should not automatically be assumed benign, underscoring the need for vigilance in their evaluation. In this case, FNA of a suspicious nodule led to the diagnosis of PTC, and thyroidectomy confirmed malignancy while resolving hyperthyroidism. Conclusion: This case highlights the critical role of early detection through ultrasound and FNA, which facilitate timely diagnosis and treatment, as clinical and radiologic assessments can be challenging in hyperthyroid patients. Thyroidectomy continues to be a definitive solution, effectively treating both hyperthyroidism and any concurrent malignancy. References: 1.Keskin C, Sahin M, Hasanov R, et al. Frequency of thyroid nodules and thyroid cancer in thyroidectomized patients with Graves’ disease. Arch Med Sci. 2020;16(2):302-307. doi:10.5114/aoms.2018.81136. 2.Cantalamessa L, Baldini M, Orsatti A, Meroni L, Amodei V, Castagnone D. Thyroid nodules in Graves disease and the risk of thyroid carcinoma. Arch Intern Med. 1999;159(15):1705-1708. doi:10.1001/archinte.159.15.1705. Presentation: Monday, July 14, 2025