Nasopharyngeal carcinoma (NPC) is commonly treated with radiotherapy and chemotherapy, particularly in advanced disease. Pneumocephalus is a rare complication of NPC and may become life-threatening when intracranial air accumulates under tension.

We report a 42-year-old man with recurrent NPC involving the skull base after prior chemotherapy and two courses of radiotherapy, with a cumulative radiation dose of 120 Gy. He presented with headache, dizziness, confusion, vomiting, and right eye ptosis. Imaging demonstrated extensive pneumocephalus involving the ventricular system and basal cisterns, and CT cisternography showed skull-base fistulization in the setting of recurrent tumor. He was initially managed conservatively, but later developed acute neurological deterioration with bradycardia and CT findings consistent with tension pneumocephalus. Emergent external ventricular drain placement with aspiration of 120 mL of air resulted in neurological recovery, and he was discharged home.

Tension pneumocephalus is a rare but serious complication that may occur in patients with recurrent NPC and skull-base involvement. Progressive tumor invasion/fistulization was the most directly supported mechanism in this case, while prior high-dose radiotherapy and suspected osteoradionecrosis may have contributed to skull-base fragility. Prompt imaging and multidisciplinary management are essential when selected NPC patients with skull-base disease develop new neurological symptoms.