Jacobson nerve schwannoma

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Jacobson nerve schwannomas are rare, benign middle ear tumors that involve the eponymous tympanic branch of the glossopharyngeal nerve. They appear as a mass on the cochlear promontory and enlargement of the inferior tympanic canaliculus .

Clinical presentation

Patients may present with hearing loss , otalgia , or pulsatile tinnitus . Otoscopic exam reveals a pale, non-pulsatile mass in the middle ear cavity .

Pathology

General pathologic features are described separately: schwannoma.

Radiographic features

CT

CT demonstrates the tumor with secondary bony changes :

  • soft tissue mass in the middle ear cavity based at the cochlear promontory
  • possible erosion of the cochlear promontory
  • expansion of the inferior tympanic canaliculus
  • no significant enhancement
MRI

The signal characteristics are typical of schwannomas elsewhere :

  • T1: hypointense
  • T2: hyperintense
  • T1 C+: homogeneous moderate enhancement

Differential diagnosis