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Abstract Disclosure: J. Yang: None. P.V. Nadkarni: None. Background: The prevalence of malignancy in a hyperfunctioning or hot thyroid nodule is considered to be low. According to the 2015 American Thyroid Association Guidelines, no cytologic evaluation is routinely recommended for hyperfunctioning nodules since they are rarely associated with malignancy (1). We present a case of a 71-year-old female with a hot nodule containing papillary thyroid cancer. Clinical Case: A 71-year-old female with Type 1 diabetes mellitus and coronary artery disease on dual antiplatelet therapy was found to have a 1.5 cm firm, non-tender right-sided thyroid nodule on a routine physical exam. Laboratory tests demonstrated low TSH 0.01 (normal 0.36 - 3.74 mIU/L) and FT4 level elevated at 1.62 (normal 0.76 -1.46 ng/dL). She noticed palpitations and started on low dose Methimazole. Thyroid ultrasound results showed a 2.1 x 2.0 x 2.0 cm right inferior lobe thyroid nodule. This thyroid nodule appeared mixed cystic and solid, hypoechoic, not taller than wide, with ill-defined margins and peripheral calcifications (ACR TI-RADS risk category: TR4). Nuclear medicine thyroid uptake scan demonstrated focally increased activity in the right lower pole corresponding with her right inferior thyroid nodule seen on ultrasound. Remainder of the gland appeared suppressed. She was recommended for ultrasound-guided fine needle aspiration biopsy of her right inferior thyroid nodule, given concerning characteristics on ultrasound findings despite results consistent with a hot nodule. Timing of her antiplatelet therapy was coordinated with her cardiologist, and her biopsy procedure scheduled after she stopped dual antiplatelet therapy. Her FNA results showed clusters of follicular cells with nuclear and architectural atypia, suspicious for papillary thyroid carcinoma. She underwent right thyroid lobectomy. Surgical pathology revealed 2 foci of papillary thyroid carcinoma, follicular variant (2.0 cm, 0.1 cm) and confined to the thyroid. All regional lymph nodes were negative for tumor. Methimazole was discontinued post-operatively, and she started Levothyroxine suppression therapy. Discussion: We present a rare association of papillary thyroid carcinoma presenting as a hot thyroid nodule. Though uncommon, detection of a hyperfunctioning thyroid nodule does not exclude the possibility of thyroid carcinoma and warrants careful evaluation. Clinicians should retain a high index of suspicion particularly when ultrasonography demonstrates findings suspicious for malignancy and consider additional evaluation with fine needle aspiration. Reference: (1) Haugen BR, Alexander EK, Bible KC et al. 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer. Thyroid. 2016 Jan;26(1):1-133. Presentation: 6/2/2024
Yang et al. (Tue,) studied this question.