Pathologic features of the inner ear in congenital deafness.

We present the morphologic findings of the temporal bones and brain of a patient with congenital deafness. We discuss these findings in relation to pathologic observations in other reported cases of congenital deafness. Morphologic abnormalities in the patient were mainly in the pars inferior of the membranous labyrinths. The osseous labyrinths were well developed. There was severe dilation of the cochlear duct with herniation of the Reissner membrane, extensive atrophy of the stria vascularis that was associated with calcified thrombi to the strial vessels, encasement of the tectorial membrane in a syncytium, and dyspiastic or regressive degeneration of the organ of Corti. Absence of spiral ganglion cells and their fibers was a prominent feature. The extensive and varied pathologic changes that were present in our patient simultaneously suggest a congenital abnormality in endolymph production and raise the possibility of anomalous development of the labyrinthine vasculature.