Temporal Bone Histopathology of Necrotizing External Otitis

Abstract

Histopathological examination of the temporal bone of an individual with necrotizing external otitis revealed severe inflammation with necrosis in the subcutaneous granulation tissue in the external auditory canal. Erosion of the bony walls of the canal had created a defect in the anterior wall, through which infection spread to the preauricular region. The lateral part of the middle ear cavity was also filled with granulation tissue and purulent exudate. A dehiscence of the horizontal portion of the facial canal had apparently allowed spread of an inflammatory round cell infiltrate along the facial nerve up to the fundus of the internal auditory canal. The only evidence of inner ear pathology was the presence of eosinophilic fluid material in the perilymphatic spaces of the labyrinth. A review of other reports of cases of necrotizing external otitis seems to show that this is the only instance of this disease in which infection spread from the external canal through the tympanic membrane to the middle ear and thence to the internal auditory canal.