Giant Spontaneous Epidural Pneumatocele: Case Report and Review of the Literature

BACKGROUND: Pneumocephalus is a commonly encountered finding in neurosurgery in which air displaces intracranial cerebrospinal fluid after cranial surgery or a cerebrospinal fluid leak into paranasal or mastoid sinuses. When an intracranial air collection becomes chronically established in a fixed loculation causing mass effect, pneumatocele is a more appropriate term. We present an unusual case of a spontaneous giant frontotemporal epidural pneumatocele that persisted for more than 1 year before the patient presented for neurological treatment. CASE DESCRIPTION: A 40-year-old man with a remote history of minor head trauma presented with symptoms of headaches, dizziness, and vertigo. Imaging revealed a right giant epidural pneumocephalus secondary to bony dehiscence of the intracranial wall of the mastoid bone. A subtemporal middle fossa approach was performed to repair the mastoid defect with hydroxyapatite, fat graft, and temporalis fascia. The patient was discharged on postoperative day 2 with improvement in his headaches. One month after discharge operative imaging demonstrated complete resolution of his epidural pneumatocele and improvement in his headaches. CONCLUSIONS: This unique case represents the first reported case in the neurosurgical literature of a giant spontaneous epidural pneumatocele occurring in an adult treated with a middle fossa approach with resolution on follow-up imaging.