Intracerebral pneumocephalus is commonly associated with head and facial trauma, ear infection, tumors and surgical interventions. Osteomas are relatively common, benign tumors that occur mainly in the paranasal sinuses, the frontal sinus in particular. Pneumocephalus has been commonly reported with frontal osteoma but isolated presentation as frontotemporal dementia is uncommon. Patient was admitted with complaints of change of behavior and forgetfulness for the last one year. He had progressively become more apathetic and presented with behavioral abnormalities. General physical examinations were within normal limits including the motor and sensory system although neuropsychiatry assessments were below the average level, with features of dementia. Further, MRI brain revealed pneumocephalus in bilateral frontal lobe. CT cisternography revealed a well defined lobulated densely sclerotic lesion of approximate size 20 × 17 × 27mm transverse and cranio-caudal axis respectively arising from right ethmoid sinus. Clinically, the association of pneumocephalus and isolated presentation as frontotemporal dementia has not been described to the best of our knowledge. A single case has been described with ethmoid osteoma. Radiological features were suggestive of osteoid osteoma. The uniqueness of the case is the development of dementia with frontotemporal involvement and resemblance with Frontotemporal Dementia. This is the only case with dementia and pneumocephalus (secondary to osteoid osteoma) to best of our knowledge.
Keywords: Ethmoid Osteoma; Mount-Fuji Sign; Pneumocephalus.