Sequential Development of Papillary Thyroid Carcinoma in Unilateral Graves' Disease: A Case Report

Background: Unilateral Graves’ disease (UGD) is a rare form of Graves’ disease (GD) characterized by hyperactivity confined to one thyroid lobe. Although thyroid cancer is associated with GD, its coexistence with UGD is exceptionally rare. Case Report: A 35-year-old woman with GD, treated with methimazole, became pregnant and remained euthyroid during pregnancy after discontinuing methimazole. Four months after delivery, she was diagnosed with mild hyperthyroidism (TSH=0.05 Thyroid scintigraphy showed increased radiotracer in the right lobe, while an ultrasound revealed a 13×10×8 mm nodule with a hypoechoic, taller-than-wide appearance. A fine-needle aspiration biopsy was suspicious for papillary thyroid carcinoma (PTC), which was confirmed after total thyroidectomy. Conclusion: unilateral Graves’ disease (UGD), similar to the typical form, can occur alongside thyroid cancer. A thorough evaluation of thyroid nodules in UGD using imaging and cytology is essential for accurate diagnosis and timely treatment.