Anaplastic thyroid carcinoma with bilateral internal jugular vein tumour thrombus formation: a case report.

Anaplastic thyroid carcinoma (ATC) is a highly aggressive thyroid malignancy, comprising 1%-4% of thyroid cancers, with rapid local invasion and distant metastasis. We report a 57-year-old male with ATC presenting with a neck mass, hoarseness, and dysphagia. Imaging showed cancer thrombus in bilateral internal jugular veins, with a biopsy confirming ATC. This case highlights the imaging and pathological features of ATC and emphasizes the importance of ultrasound in evaluating intravascular cancer thrombus, aiding accurate diagnosis and management.