Rare Case of Internal Jugular Vein Thrombosis Associated With Squamous Cell Carcinoma of the Posterior Tongue.

Internal jugular vein thrombosis (IJVT) is an uncommon but potentially life-threatening condition, arising from diverse risk factors including infection, instrumentation, and malignancy. Although its incidence in head and neck (H&N) cancers remains low, early recognition is essential, as serious complications such as pulmonary embolism, stroke, and superior vena cava obstruction can arise. We report the case of a 77-year-old man with a remote history of treated H&N malignancy, who had a new diagnosis of base-of-tongue squamous cell carcinoma (scc) after he developed a right-sided neck swelling. He showed initial improvement with palliative radiotherapy. He presented again a couple of months later with bilateral facial swelling extending to the right neck, initially treated as facial cellulitis. However, antibiotics proved ineffective, leading us to investigate further. Subsequent contrast-enhanced arterial-phase CT findings were in line with a bland right IJVT, for which anticoagulation was commenced promptly. This case highlights the importance of considering provoked IJVT in patients with H&N SCC who present with persistent neck or facial swelling, even in the absence of other systemic risk factors. Early diagnostic imaging and timely anticoagulation may prevent potentially fatal thromboembolic complications.