A 64-year-old woman underwent a suboccipital craniectomy for the removal of an acute posterior fossa subdural hematoma. On the first postoperative day, she became agitated with a depressed level of consciousness. An immediate brain computed tomographic scan showed a massive accumulation of air in the subdural space of the cranial cavity with compressive effects on both frontal lobes, ie, "Mount Fuji sign," thereby confirming the diagnosis of tension pneumocephalus (Figure 1).
Sadeghian H. Mount Fuji Sign in Tension Pneumocephalus. Arch Neurol. 2000;57(9):1366. doi:10.1001/archneur.57.9.1366