Labyrinthitis ossificans (LO) is characterized by new bone formation in the cochlea and vestibule and most commonly is the end-stage sequela of purulent labyrinthitis.1 Purulent labyrinthitis usually occurs as a result of bacterial meningitis. In meningitic labyrinthitis, infection reaches the inner ear from the subarachnoid space via the cochlear aqueduct or the internal auditory meatus. Labyrinthine infection can also occur as a result of bacterial middle ear infections, from direct spread through the oval or the round windows,2,3 or by seeding of the labyrinth from the hematogeneous route.1,2 In addition to purulent labyrinthitis, other etiopathologic causes of LO include vascular obstruction of the labyrinthine artery, temporal bone trauma, autoimmune inner ear disease, otosclerosis, leukemia, and tumors of the temporal bone.
Radiology Quiz Case 1: Diagnosis. Arch Otolaryngol Head Neck Surg. 2007;133(3):300. doi:10.1001/archotol.133.3.300-a