Background Headache, one of the most common symptoms presenting to the emergency department, is usually benign but sometimes fatal. Identifying high-risk headache syndromes and providing appropriate headache therapy remain the first priority for emergency physicians. Common "Red flags" includes sudden onset, focal neurological deficit, fever, neck stiffness and so on. We categorize headache into primary (such as tension, cluster headache and migraine) and secondary (subarachnoid hemorrhage,

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... e meningitis, intracranial hemorrhage, etc) while ruling out secondary headache is the first step in management. Case presentation We report a case of nasopharyngeal carcinoma(NPC) with defect at left side of nasopharynx and sphenoid sinus causing diffuse pneumocephalus. The 35-year-old male presented to the emergency department for sudden-onset headache with unusual associated symptom: rhinorrhea. Computed tomographic (CT) examination revealed a diffuse pneumocephalus, which did not present in magnetic resonance imaging of brain one month ago. The treatment was mainly conservative and the recovery was smooth.Conclusions Unusual symptoms like rhinorrhea and otorrhea should not be ignored, they might be the only clues to the diagnosis of pneumocephalus. Most of the pneumocephalus related to NPC occurred after recent radiotherapy. However, this patient finished radiotherapy on 2012/5. Thus, metastatic skull bony erosion with associated pneumocephalus might be taken into consideration.