Meningoencephalic herniation into the middle ear.

Meningoencephalic herniation into the middle ear (MHME) is a rare condition. It can result from ear surgery, infection, head trauma or can be spontaneous. Diagnosis requires a high degree of clinical suspicion. The presentation may suggest the condition, but sometimes the intraoperative discovery of an occult meningoencephalic herniation may be a frightening situation. Treatment planning must avoid intra-cranial complications. Transmastoid (TM) and middle cranial fossa (MCF) are alternative or complementary approaches, determined by several factors, including the size and the site of the bony defect and the presence or absence of middle ear infection. Three case reports are presented and a review of the literature is performed, to explain some aspects related to MHME, including aetiopathogenesis, clinical presentation, histopathology, diagnosis and treatment.