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Cholesteatoma

Summary

  • Cholesteatoma is a benign but locally destructive lesion of the temporal bone, characterised by an accumulation of keratinizing squamous epithelium
  • It typically presents with chronic otorrhea, hearing loss, and potential complications due to erosion of surrounding structures
  • Imaging plays a crucial role in diagnosis, surgical planning, and follow-up1

Pathophysiology

  • Two main types:
    • Congenital: Remnant of embryonic epithelial tissue in the middle ear
    • Acquired: Most common, develops from retraction pocket in pars flaccida of tympanic membrane
  • Growth occurs through accumulation of desquamated keratin and debris
  • Expansion leads to bone erosion through pressure necrosis and enzymatic activity

Demographics

  • Incidence: 3 per 100,000 in children, 9.2 per 100,000 in adults
  • Slightly more common in males
  • Peak incidence in second and third decades of life
  • Risk factors:
    • Chronic otitis media
    • Eustachian tube dysfunction
    • Craniofacial abnormalities (e.g., cleft palate)

Diagnosis

  • Clinical presentation:
    • Chronic otorrhea
    • Progressive conductive hearing loss
    • Otalgia
    • Vertigo (in advanced cases)
  • Otoscopic examination:
    • Retraction pocket or attic perforation
    • White or pearly mass behind tympanic membrane
  • Audiometry:
    • Conductive hearing loss
    • Sensorineural component in advanced cases

Imaging

  • CT (non-contrast):
    • Modality of choice for initial evaluation and surgical planning
    • Findings:
    • Soft tissue mass in middle ear or mastoid
    • Bone erosion (scutum, ossicles, tegmen tympani)
    • Widening of aditus ad antrum
    • Labyrinthine fistula (in advanced cases)
  • MRI:
    • Complementary to CT, especially for follow-up and recurrence detection
    • Findings:
    • T1: Intermediate to low signal intensity
    • T2: Heterogeneous, predominantly high signal intensity
    • Diffusion-weighted imaging (DWI): Restricted diffusion, high signal on b1000 images
  • Non-echo planar diffusion-weighted imaging (non-EPI DWI):
    • Higher sensitivity for small cholesteatomas and recurrence detection

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  • A 20-year-old patient presented with a facial nerve palsy and sensorineural hearing loss.
  • CT showed erosion of the petrous bone including the posterior wall of the internal auditory canal and the wall of the labyrinthine and tympanic facial canal.
  • MRI showed a non-enhancing, T2-hyperintense lesion causing diffusion restriction.

Treatment

  • Surgical removal (tympanomastoidectomy)
  • Non-EPI DWI is the mainstay for detecting residual/recurrent disease on follow-up, avoiding second-look surgery
  • Untreated disease can erode into the labyrinth, facial canal or intracranial compartment

Differential diagnosis

Differential Diagnosis Distinguishing Feature
Chronic otitis media Lack of keratin debris on imaging
Epidermoid cyst Markedly restricted diffusion; typically occurs in CPA cistern or other extra-otologic sites
Paraganglioma Characteristic "salt and pepper" appearance on MRI
Cholesterol granuloma Hyperintense on T1-weighted MRI
Langerhans cell histiocytosis Typically multifocal lesions

  1. Yung et al. EAONO/JOS Joint Consensus Statements on the Definitions, Classification and Staging of Middle Ear Cholesteatoma. 2017. The journal of international advanced otology - Open in new tab. ↩