Temporal bone pneumocele with large intracranial epidural extension

Backgrounds: To describe presentation, diagnosis and management of a case of spontaneous temporal bone pneumocele with large intracranial extension and brain compression associated with external auditory canal pneumatocele. Methods: A 34-year-old male patient was referred for a large intracranial epidural air collection compressing the right cerebral hemisphere. The patient was asymptomatic except for persisting fullness of the right ear for which he performed frequent Valsalva maneuvers. CT scan showed luminal enlargement of right temporal bone with thinning of the limiting bone, focal dehiscences at the level of the external auditory canal (EAC) and the medial wall of the mastoid tip and remodeling of the calvarial bone. Audiometry was normal bilaterally. A retroauricular transmastoid approach was performed reconstructing the defect in the EAC using bone paste and fibrin glue. The epidural cavity was sealed off by means of temporalis fascia, abdominal fat graft and fibrin glue. Results: After 17 months, MRI showed complete resolution of the intracranial air collection with expansion of the right cerebral hemisphere. Conclusions: Intracranial extension of a temporal bone pneumocele is a rare condition due to progressive expansion of mastoid pneumatization in the epidural space with bone resorption, enlargement of the aerial spaces and chronic calvarial bone changes. Repeated Valsalva maneuvers may sustain the remodeling process. Although usually asymptomatic, there is high risk of acute mass effect particularly in case of trauma and infections. A correct diagnosis is the necessary premise for appropriate treatment.