Concurrent Papillary Thyroid Carcinoma and Anaplastic Thyroid Carcinoma Presenting With Hoarseness and Dysphagia.

Anaplastic thyroid carcinoma is a rapidly progressive thyroid malignancy associated with extensive local invasion and limited survival. We describe the case of a 60-year-old man who developed new-onset dysphagia and voice changes in the setting of a thyroid mass. Initial cytology and core sampling were consistent with papillary thyroid carcinoma, yet the patient's accelerating compressive symptoms led to expedited total thyroidectomy. Surgical pathology ultimately demonstrated conventional papillary carcinoma with discrete foci of undifferentiated carcinoma within the same specimen. This case highlights that rapidly progressive compressive symptoms in a patient with cytology-proven conventional papillary thyroid carcinoma may indicate an occult, unsampled anaplastic component, even in the absence of high-risk features on preoperative evaluation. The presence of both differentiated and undifferentiated components broadens the differential considerations regarding tumor evolution and highlights the need for close clinicopathologic correlation. Prompt recognition of alarming symptoms and early multidisciplinary coordination were central to management, particularly to mitigate the risk of airway compromise and to guide timely postoperative systemic therapy.