Fig. 10

Abnormal enhancement in the IAC due to leptomeningeal disease. This male adult presented with bilateral sensorineural hearing loss and asymmetric facial palsy. On MRI, thickening (a, b: 3D T2 TSE) and enhancement (c, d: contrast-enhanced T1) of the seventh and eighth cranial nerves as well as the cochlea is seen bilaterally, suggestive of a systemic infectious or inflammatory disease. Laboratory findings confirmed infection with Treponema pallidum. Labyrinthine involvement may occur in the secondary or primary stage of acquired syphilis, resulting from meningovascular and acute meningitic forms of neurosyphilis. Luetic syphilis may be accompanied by osteitis of the temporal bone. The permeative demineralisation of the bone may mimic the imaging appearance of otosclerosis, osteogenesis imperfecta or Paget’s disease