50% OFF! Cervical Spine X-ray Course by Matt Skalski Offer ends Monday

Cholesteatoma

Cholesteatomas are histologically-equivalent to an epidermoid cyst and are composed of desquamated keratinizing stratified squamous epithelium forming a mass.

They may be asymptomatic, or may present with conductive hearing loss, dizziness, or otorrhea.

The mass is lined by epithelium (facing inwards) which continues to grow, thereby shedding additional cells into the mass. Their cholesterol content (which is not always present) is responsible for their name, although 'keratoma' is probably a more apt term.

Cholesteatomas of the temporal bone and middle ear can be divided into:

Conventional non-contrast MR imaging with diffusion-weighted imaging is recommended in all patients with a suspicion of cholesteatoma. An MRI should be performed especially in patients with previous surgery for cholesteatoma since recurrence or residual tumor can be detected with great accuracy. If negative, it can obviate "second look" surgery. It is important to prepare the patient for the examination (clear the external auditory canal or the postoperative cavity) to avoid a false positive diagnosis.

The standard examination is a T2-weighted series in the coronal and axial plane, followed by a non-echo planar DWI series (b-values 0, 1000). On the DWI images with b-value 1000 s/mm2, a cholesteatoma becomes apparent as a hyperintense area. The signal intensity should be higher than visible on the DWI images with b-value 0 s/mm2. On the ADC map, a low signal should be visible in the same area, confirming the presence of diffusion restriction.

With these findings, recurrent cholesteatoma can be detected with 100% specificity. Cholesteatomas down to a size of 2 mm can be detected with this technique on a 1.5 T MRI machine.

A CT scan should be added in those cases where a cholesteatoma is detected with MRI. CT is required for preoperative planning (reconstruction of ossicles if needed) and to exclude perforation of the bony tegmen.

The pars flaccida cholesteatoma originates in Prussak space and usually extends posteriorly, while the pars tensa cholesteatoma originates in the posterior mesotympanum and tends to extend posteromedially.

Generally, surgical excision is eventually necessary 9. Excision is often performed with tympanoplasty ± mastoidectomy ± ossicular reconstruction, depending on extent of disease 9.

The main differentials, which unlike cholesteatoma show a high signal on the ADC map, are:

Further differential diagnoses include:

  • cerumen: which shows similar image characteristics to cholesteatoma but is located in the external ear canal
  • abscess formation in the middle ear: can also show similar imaging findings but has a completely different clinical presentation

Important CT features to comment on when reporting a cholesteatoma:

Article information

rID: 1116
Tag: refs, refs, refs
Synonyms or Alternate Spellings:
  • Middle ear cholesteatoma

ADVERTISEMENT: Supporters see fewers/no ads

Cases and figures

  • Case 1
    Drag here to reorder.
  • Case 2: acquired - likely pars flaccida type
    Drag here to reorder.
  • Case 3: on left
    Drag here to reorder.
  • Case 4: DWI + T2 fusion
    Drag here to reorder.
  • Case 5
    Drag here to reorder.
  • Case 6
    Drag here to reorder.
  • Case 7: bilateral cholesteatoma
    Drag here to reorder.
  • Case 8
    Drag here to reorder.
  • Case 9: DWI + CT fusion
    Drag here to reorder.
  • Case 10
    Drag here to reorder.
  • Case 11: mural
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.