8742 Exploring the Clinical Landscape of Papillary Thyroid Microcarcinoma with Lymph Node Metastasis: A Single-Institution Case Series and Implications for Treatment Decisions

Abstract Disclosure: F. Manas: None. R. Nakdali: None. D. Aljbour Almajali: None. A. Bhan: None. R. Simon: None. Introduction: Papillary thyroid microcarcinomas (PTMC) refer to papillary thyroid carcinomas with primary tumor size ≤ 1cm. Characterized by their indolent nature, PTMCs boast a mortality rate of less than 1%. Loco-regional spread occurs in approximately 2-6% of cases, while distant metastasis is observed in about 1-2%. Notably, the rate of recurrence after lymph node (LN) metastasis can reach up to 20%. The optimal management of PTMC remains controversial with some studies suggesting no discernible difference in clinical outcomes between patients undergoing active surveillance and those opting for surgical removal. There is limited research on thyroid cancer oncogenes that can predict the progression of PTMC outside of the thyroid gland. We report the clinical outcomes of a series of patients with PTMC who presented with LN metastasis at our institution.Case Series: We describe five patients diagnosed with papillary thyroid microcarcinoma with LN metastasis. All patients presented with a neck mass and evaluation by fine needle aspiration (FNA), showed papillary thyroid cancer. The tumor sizes ranged from 0.15 cm to 1 cm and all cases had extensive LN involvement, with sizes ranging from 0.7 to 4.5 cm. All patients received adjuvant RAI according to ATA guidelines. Molecular testing was not available for any of these patients.Discussion: Our case series offers valuable insight into the clinical outcomes of individuals with PTMC who underwent total thyroidectomy with LN dissection. We postulate that there are two separate groups of patients with PTMC. One group with indolent disease, which lends itself to careful follow-up, even without surgery, and the other group with aggressive disease at presentation. The challenge lies in the correct classification of the patient at baseline so that therapy is tailored to the type of cancer. We need better predictors of disease severity so that patients can be risk-stratified appropriately. The absence of clear guidelines regarding the optimal extent of surgery for PTMC adds complexity to treatment decisions. Nevertheless, our case series sheds light on the infrequent occurrence of PTMC with LN metastasis. It is noteworthy that despite the absence of a mutational profile for these patients, consistent with prior small-scale studies, no genetic alterations have been identified as reliable predictors of LN metastasis in PTMC. Our findings underscore the imperative for further investigative studies to enhance our ability to predict more aggressive cases of PTMC. By addressing the gap in knowledge, future research endeavors may contribute to the refinement of treatment strategies for individuals with PTMC. Presentation: 6/1/2024