Temporal bone pathology in a case of Cogan's syndrome.

Cogan's syndrome (CS) presents typical and atypical types. Typically, there are episodes of nonsyphilitic keratitis and audiovestibular dysfunction. Atypically, there are inflammatory changes in other eye structures and other organ systems, particularly the cardiovascular system. The temporal bone pathology in a case of CS shows changes that are similar to those observed in other autoimmune disorders associated with audiovestibular dysfunction. The following pathologic features characterize autoimmune inner ear disease: 1. acute labyrinthitis resulting in atrophy of inner ear tissues including the sense organs and their supporting structures; 2. endolymphatic hydrops; 3. focal and diffuse proliferation of fibrous tissue and bone; and 4. retrograde neuronal degeneration. These pathologic findings are consistent with an inflammatory (and possibly ischemic) attack on the membranous labyrinth.