Temporal bone pathology of adult-type osteopetrosis.

We present the pathologic features in the temporal bones of a 62-year-old woman with the adult benign form of osteopetrosis. Most of the bony tissue was expanded by dense lamellar bone, with, in some places, the presence of residual calcified cartilage. In the otic capsule, globuli interossei were greatly increased in number. The ossicles were enlarged with fixation of the stapes. Narrowing of mastoid air cells, the internal auditory meati, and eustachian tubes was present, the latter associated with chronic otitis media. The bone deposition in the ossicles contributed to the conductive hearing loss, which was a prominent feature in this patient's otologic findings. The narrowing of the internal auditory meati may similarly have contributed to a degree of sensorineural hearing loss.