SUN-562 Hurthle Cell Carcinoma Presenting as Hyperfunctioning Nodule

Background: Hurthle cell carcinoma (HCC) is a rare type of aggressive follicular carcinoma comprising a small percentage of all thyroid cancers. It is associated with high metastasis and mortality rates with 20-30% of this type of cancer having metastatic extension at the time of treatment. HCC may be asymptomatic until a lump is noticed on the anterior neck. The inability to establish a preoperative diagnosis of HCC creates a dilemma with hyperfunctioning thyroid nodules which are commonly managed as benign. Clinical Case: This is a case of a 48-year old female, who presented with a multinodular thyroid gland on initial imaging associated with palpitations and chest discomfort. Further workup revealed subclinical hyperthyroidism and a thyroid scan showing hyperfunctioning nodules on both lobes. She underwent fine needle aspiration (FNA) biopsy which revealed benign colloid nodule on the right thyroid and cellular findings consistent with follicular neoplasm with oncocytic features on the left thyroid nodule prompting surgery. Surgical specimen histopathology eventually revealed Hurthle cell carcinoma with lymphovascular invasion of the left thyroid nodule. Conclusion: Hurthle cell carcinoma is a relatively uncommon thyroid neoplasm. Though toxic nodules are rarely malignant, HCC is more commonly seen in hyperfunctioning nodules compared with general thyroid nodules. This case supports further evaluation of toxic nodules for possible risk of thyroid cancer. Reference: (1) Mirfakhraee, Sasan & Mathews, Dana & Peng, Lan & Woodruff, Stacey & M Zigman, Jeffrey. (2013). A solitary hyperfunctioning thyroid nodule harboring thyroid carcinoma: Review of the literature. Thyroid research. 6. 7. 10.1186/1756-6614-6-7.