Temporal bone findings in craniodiaphyseal dysplasia.

To our knowledge, this is the first description of the histopathology of the temporal bone from a case of craniodiaphyseal dysplasia. The air spaces of the mastoid, external auditory canal, and middle ear cavity are reduced by hyperostotic bone. The ossicles are also deformed by the bony overgrowth. Anomalous ossicles with hyperostosis could affect the air conduction. Even though the internal auditory canal is somewhat elongated and narrow, no labyrinthine abnormalities can be attributed to the abnormal bone. Facial nerves run through abnormal courses but the geniculate ganglion cells are not involved. The VIIIth nerve dysfunction in this case could be due to mechanical damage of the nerve fibers and/or impaired vascular supply by the hyperostosis.