Diversity of the cochlear and vestibular pathologies in human temporal bones of newborns infected with cytomegalovirus.

Hypothesis: Human temporal bones of newborns with congenital cytomegalovirus (cCMV) infection can be characterized by diverse cochlear and vestibular histopathologies associated with the variability in sensorineural hearing loss (SNHL) and vestibular dysfunction in these newborns. Background: Only a small number of studies on the cochlear and vestibular pathologies in human temporal bones with cCMV infection have been previously reported. Methods: Cochleovestibular histopathologies were evaluated in 4 temporal bones from 3 infants with cCMV infection by light microscopy. Results: In one available temporal bone of the infant in Case 1, no cytomegalic cells were found. Large areas of cellular and non-cellular structures were observed in the scala tympani of the perilymphatic space; however, there was no obvious loss of cochlear or vestibular hair cells. In Case 2, cytomegalic cells, a loss of vestibular hair cells, and a loss of nerve fibers were observed only in the area of dark cells in the vestibular labyrinth of the left temporal bone. No cytomegalic cells were found in the right temporal bone of the same infant; however, there was a loss of outer hair cells in the organ of Corti and hypervascularity in the stria vascularis. The one available temporal bone of the infant in Case 3 showed cytomegalic cells and a loss of hair cells in both cochlear and vestibular parts of the inner ear. Conclusions: Human temporal bones of newborns with cCMV demonstrate diverse cochleovestibular histopathologies. This diversity is consistent with the variable SNHL and vestibular dysfunction reported in infected newborns.