Bilateral Middle Cranial Fossa Encephaloceles Showcasing Tegmen Tympani and Tegmen Mastoideum Defects

This radiographic case report showcases one patient with bilateral middle cranial encephaloceles: one of the tegmen mastoideum defects on right and another of the tegmen tympani defect on the left. The patient underwent transmastoid repair of both encephaloceles. On the left, the meningoencephalic herniation was adjacent to the body of the incus, and this was easily reduced with bipolar cautery. On the right, the meningoencephalic herniation filled the epitympanum and reached the middle ear space; encephalocele repair required removal of the incus and the head of the malleus, with later ossicular chain reconstruction. Bilateral CT and MR images are available on axial, coronal, and sagittal views. This case highlights the radiographic differences between tegmen tympani and tegmen mastoideum defects and herniation of intracranial contents.