Hydrops due to syphilitic endolymphatic duct obliteration.

Three pairs of temporal bones with otologic syphilis were studied histopathologically to detect obliteration of the endolymphatic duct and the associated hydrops. All cases showed infiltration and obliteration of the endolymphatic duct by round cells, giant cells, and fibrous tissue. These findings may be related to failure of medical treatment and sac surgery to arrest or alleviate symptoms of advanced syphilis.