MON-484 Thyroid Nodules: Not so Simple to Manage

Abstract

Thyroid Nodules: Not So Simple to Manage Thyroid nodules diagnosis and malignancy risk stratification remains a challenge for decision making between conservative vs invasive management. The development of the clinical guidelines provides alternatives for evaluation and management for thyroid nodules, but can be used for all patients? A 43 y/o female without known past medical history is referred to the endocrine service by her primary care physician for evaluation of a thyroid nodule. She was presenting with 1 month history of mild discomfort on the neck and was evaluated with thyroid US that was relevant for multiple bilateral solid nodules measuring <1.0cm and a one spongiform measuring 1.7 x 1.2 x 1.3cm in the right lobe extending minimally to the capsule laterally and to the carotid artery wall. Patient denies cough, hoarseness, odynophagia, shortness of breath, family history of thyroid cancer or radiation exposure. On examination there were no goiter nor palpable thyroid nodules, as well as no clinical signs and symptoms of thyroid disease. Patient is clinically and biochemically euthyroid with a very low suspicion thyroid nodule (3% estimated malignancy risk). Despite nodule is below the 2.0cm cutoff point for fine needle aspiration biopsy (FNAB) according to American Association of Clinical Endocrinologist (AACE) and American Thyroid Association (ATA) guidelines, it was done based on additional suspicious sonographic features detect by the endocrinologist on evaluation of ultrasound images. FNAB was performed and reveals Atypia of undetermined significance/Follicular Lesion of undetermined significance (AUS/FLUS) Bethesda system category III with a risk of malignancy of 5–15%. Patient was reluctant to surgery given the very low risk nodule and biopsy results of AUS/FLUS. In order to further manage this patient with undetermined significance thyroid nodule, Gene Expression Classifier (GEC) Molecular Analysis (AFIRMA) was performed. AFIRMA test was done with a second FNAB that also reveals AUS/FLUS but was found positive for BRAFv600, Bethesda system category IV: Suspicious of Papillary Thyroid Carcinoma. BRAFv600 is the only mutation that have high specificity (99%) for papillary thyroid carcinoma and is associated with increased disease-specific mortality, aggressive histologic phenotypes, lymph node metastases, extrathyroidal extension and risk of recurrence. Based on this data patient now have 95% risk of malignancy and requires surgical therapy. Patient preferred total thyroidectomy over lobectomy; pathology results shows 2.0cm Papillary Thyroid Carcinoma Stage I (T1N0M0). Despite very low risk nodule finding, malignancy was diagnosed. As depicted in this case, thyroid nodules aren’t so simple to manage, and their management should involve imaging and pathology findings along with clinical judgement and patient individualization in decision making process.