Middle ear cholesteatoma - imaging findings

Key findings in acquired and congenital middle ear cholesteatoma.
From Radiopaedia.org and Diagnostic Imaging: Head and Neck by H. Ric, Harnsberger.
https://radiopaedia.org/articles/cholesteatoma?lang=us
https://radiopaedia.org/articles/congenital-cholesteatoma?lang=us
https://radiopaedia.org/articles/acquired-cholesteatoma?lang=us
https://radiopaedia.org/articles/prussak-space?lang=us

1. Middle ear cholesteatoma Imaging findings Maria Cucos MD

2. Types of middle ear cholesteatoma (ME Ch) acquired pars flaccida (PF) pars tensa (PT) congenital

3. Acquired cholesteatoma secondary to chronic ME infection and tympanic perforation 95% of all Ch and most frequent ME -mastoid mass 80% in Prussak space tympanic membrane not intact  retracted or perforated Congenital cholesteatoma epidermoid inclusion cysts 5% of all Ch petrous apex > ME tympanic membrane intact

4. Cholesteatoma on CT soft tissue mass mass effect bone erosions

5. Bone erosions to report in cholesteatoma scutum lateral wall of tympanic cavity ossicles mastoid tegmen tympani lateral semicircular canal facial nerve canal oval and round window

6. Acquired cholesteatoma when ME and mastoid completely opacified  difficult ddx effusion vs cholesteatoma  ossicular erosion supports Ch  but ossicular erosion can also happen with chronic otomastoiditis  scutum erosion further supports Ch

7. Pars flaccida cholesteatoma more common than PT Ch originates in Prussak space  scutum erosion extends posterosuperiorly  epitympanum and mastoid lateral to ossicles  ossicle erosion starts laterally

8. Pars tensa cholesteatoma if small, seen in facial recess and sinus tympani of posterior wall of mesotympanum often medial to ossicles  ossicle erosion starts medially spreads to ossicles , aditus , and mastoid

9. Consider PT Ch if mass centered posteriorly , medial to ossicles ossicles displaced laterally ossicle erosion starts medially

10. Cholesteatoma on MRI  think of epidermoid cysts in the brain T1 hypo T2 hyper FLAIR no attenuation or only partial attenuation ≠ cholesterol granuloma which never attenuates T1 C+ thin rim enhancement DWI restricted diffusion with low ADC

11. Cholesteatoma on MRI variant of congenital Ch: white epidermoid T1 hyper, T2 hyper indistinguishable from cholesterol granuloma

12. Complications of cholesteatoma perilymphatic fistula labyrinthitis meningitis cerebral abscess petrous apicitis

13. Ask clinician about otoscopy tympanic membrane intact or perforated/retracted? color and location of retrotympanic mass

14. Remember perforated/retracted tympanic membrane soft tissue mass with bone erosions Prussak space diffusion restriction