Pars flaccida cholesteatoma

Findings

There is an 8mm mass in Prussak’s space with erosion of the malleus and scutum.

Differential diagnosis:
- Pars flaccida cholesteatoma
- Cholesterol granuloma
- Paraganglioma
- Pars tensa cholesteatoma


Diagnosis: Pars flaccida cholesteatoma


Key points

A pars flaccida cholesteatoma often occurs when a patient has chronic middle ear inflammation and/or TM perforation. The cholesteatoma forms when there is an accumulation of stratified epithelial cells in Prussak's space. The cholesteatoma can be seen in all age groups, but tend to be more aggressive in children. Patients can present with aural discharge, conductive hearing loss, and otalgia. Early treatment with surgery can preserve hearing.


Radiologic overview of the diagnosis

A pars flaccida cholesteatoma appears as a mass in Prussak's space with erosion of the scutum and/or adjacent ossicle. Ossicle erosion is seen ~70% of the cases. There is no enhancement of the cholesteatoma itself, though surrounding granulation tissue may enhance.

High resolution temporal bone CT is the best modality to evaluate a suspected cholesteatoma. A pars tensa cholesteatoma is far less common and involves the sinus tympanum. A cholesterol granuloma appears blue on otoscopy and may have similar bony erosions as that of a cholesteatoma. A paraganglioma appears as a cherry red mass on otoscopy and usually does not erode bone.

In this case, there is an 8mm mass in Prussak's space with erosion of the malleus and scutum.