Middle Ear Lesion

Middle Ear Lesion
H. Ric Harnsberger, MD
DIFFERENTIAL DIAGNOSIS
Common
  • Chronic Otitis Media (COM)
  • Acquired Cholesteatoma, Pars Flaccida
  • Congenital Cholesteatoma, Middle Ear
Less Common
  • Acute Otomastoiditis (AOM) with Coalescent Otomastoiditis
  • Acquired Cholesteatoma, Pars Tensa
  • Cholesterol Granuloma, Middle Ear
  • COM with Tympanosclerosis
  • COM with Ossicular Erosions
Rare but Important
  • Rhabdomyosarcoma, Middle Ear
  • Langerhans Histiocytosis, T-Bone
  • Dehiscent Jugular Bulb
  • Aberrant Internal Carotid Artery
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
  • Otoscopic findings often provide critical clues to precise diagnosis of middle ear lesion in child
    • Presence or absence of tympanic membrane (TM) rupture important
      • Pars tensa &/or flaccida acquired cholesteatoma has ruptured TM
    • Color and location of retrotympanic mass may be key to imaging diagnosis
Helpful Clues for Common Diagnoses
  • Chronic Otitis Media (COM)
    • Otoscopy: Thickened tympanic membrane
    • Bone CT: Linear, sporadic middle ear-mastoid tissue; mastoid air cells may be underpneumatized
  • Acquired Cholesteatoma, Pars Flaccida
    • Otoscopy: Rupture or retraction pocket affecting pars flaccida portion of tympanic membrane
    • Bone CT: Nondependent soft tissue filling Prussak space with ossicle and/or bony wall erosions
      • Possible complications: Tegmen tympani, lateral semicircular canal, facial nerve canal dehiscence
  • Congenital Cholesteatoma, Middle Ear
    • Otoscopy: White mass behind intact TM
    • Bone CT: Smooth, well-circumscribed soft tissue mass filling middle ear; often medial to ossicle chain
      • Ossicle erosion often absent
      • Mastoid pneumatization often normal
Helpful Clues for Less Common Diagnoses
  • Acute Otomastoiditis (AOM) with Coalescent Otomastoiditis
    • Otoscopy: Bulging, inflamed tympanic membrane
    • Bone CT: Complete middle ear-mastoid opacification with mastoid trabecular breakdown
      • Hint: Look on soft tissue windows for adjacent postauricular abscess or epidural abscess
  • Acquired Cholesteatoma, Pars Tensa
    • Otoscopy: Ruptured pars tensa portion of TM
    • Bone CT: Meso- and hypotympanic soft tissue mass often extending posteriorly or medially
  • Cholesterol Granuloma, Middle Ear
    • Otoscopy: Blue-black material behind intact TM
    • Bone CT: Middle ear soft tissue mass with minimal bony erosion
    • MR: High T1 and high T2 signal of material in middle ear (ME)
      • Hint: Old blood in cholesterol granuloma creates T1 shortening
  • COM with Tympanosclerosis
    • Otoscopy: Opaque, calcified tympanic membrane
    • Bone CT: Postinflammatory calcifications may affect ossicles, ligaments or TM
  • COM with Ossicular Erosions
    • Otoscopy: Thickened TM without normal ossicle impressions
    • Bone CT: Linear middle ear and mastoid air cell opacifications with partial ossicle absence
      • Long process of incus-lenticular process and stapes hub most commonly affected
Helpful Clues for Rare Diagnoses
  • Rhabdomyosarcoma, Middle Ear
    • Otoscopy: EAC “polyp”
    • Bone CT: Destructive middle ear mass that often affects EAC, ossicles, surrounding bones, overlying dura
  • Langerhans Histiocytosis, T-bone
    • Otoscopy: Postauricular mass common
    • Bone CT: Unilateral or bilateral (30%) destructive T-bone lesions affecting middle ear secondarily
      • Mastoid air cell more commonly affected than petrous apex or inner ear
  • Dehiscent Jugular Bulb
    • Otoscopy: Blue lesion behind posteroinferior quadrant of TM
    • Bone CT: Dehiscent sigmoid plate projects jugular bulb into posteroinferior middle ear cavity
  • Aberrant Internal Carotid Artery
    • Otoscopy: Reddish mass passes across inferior half of TM
    • Bone CT: Tubular lesion passes into posteroinferior middle ear cavity through enlarged inferior tympanic canaliculus
      • Aberrant ICA passes out of middle ear cavity anteroinferiorly by accessing posterolateral margin of horizontal petrous internal carotid artery
Other Essential Information
  • Best imaging tool for middle ear lesion in child: T-bone CT without contrast
    • Thin-section, fat-saturated MR only used for further evaluation of larger lesions involving inner ear, floor middle cranial fossa or sigmoid sinus-posterior fossa
  • Tumor or tumor-like lesions to consider in middle ear of child
    • Rhabdomyosarcoma and Langerhans cell histiocytosis
    • May be difficult to tell these 2 lesions apart
    • Rhabdomyosarcoma, Middle Ear
      • Unilateral; centered in middle ear cavity; may present with EAC “polyp”
    • Langerhans Histiocytosis, T-Bone
      • May be bilateral; centered around middle ear cavity, especially in mastoid; may present as postauricular mass
Alternative Differential Approaches
Aug 10, 2016 | Posted by in PEDIATRICS | Comments Off on Middle Ear Lesion

Full access? Get Clinical Tree

Get Clinical Tree app for offline access