SUN-314 Rapid Progression in Papillary Thyroid Carcinoma with Suspected High-Grade Features

Abstract Disclosure: A. Thomas: None. B. Marquez: None. L. Miranda Burgos: None. J. Godinez: None. Introduction: Thyroid nodules are commonly encountered in clinical practice, with most being benign or slow-growing malignancies. Papillary thyroid carcinoma (PTC) accounts for 80-85% of thyroid cancers and typically follows an indolent course with a favorable prognosis. However, aggressive subtypes can exhibit rapid progression and increased morbidity. This case describes a 47-year-old female with a rapidly enlarging neck mass, raising concern for an aggressive PTC variant. Case Presentation: 47-year-old female with no significant medical history presented with a one-week history of a rapidly enlarging left neck mass, associated with pain and tenderness. Examination revealed a large, firm, and tender left-neck mass with ipsilateral lymphadenopathy. Initial laboratory tests, including thyroid function tests, were unremarkable. HIV screening was negative. The patient was started on IV clindamycin and dexamethasone for symptomatic relief. Blood cultures were negative.A contrast-enhanced CT scan of the neck revealed an 8.5 cm left thyroid lobe mass displacing the trachea to the right with narrowing, along with a 5.0 cm necrotic lymph node with indistinct borders and inflammatory changes. Chest CT identified a 2 cm pretracheal lymph node, raising concern for mediastinal involvement. Ultrasound-guided fine-needle aspiration (FNA) of the thyroid mass and lymph node confirmed PTC, with immunohistochemical staining positive for CK7, PAX8, TTF-1, and GATA3. The complex morphology suggested a possible high-grade variant. Oncology and surgery teams recommended surgical resection, followed by histopathological analysis. A PET-CT was planned to assess for distant metastases. Discussion: This case highlights the atypical presentation of PTC with rapid growth, necrotic lymphadenopathy, and suspected mediastinal involvement. While classical PTC has an excellent prognosis, aggressive variants, such as tall cell or hobnail carcinoma, demonstrate higher recurrence rates and increased metastatic potential (1,2).Management of aggressive PTC involves surgery, radioactive iodine therapy, thyroid hormone suppression, and, in select cases, external beam radiation or targeted therapies. PET-CT plays a critical role in staging and guiding treatment. A multidisciplinary approach is essential for optimizing outcomes. Early intervention is crucial to improve outcomes in aggressive PTC subtypes.References: Haugen BR, et al. "2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer." Thyroid. Vuong HG, et al. "Prognostic impact of aggressive histological variants of papillary thyroid carcinoma: A meta-analysis." Endocr Relat Cancer. Presentation: Sunday, July 13, 2025