A non-dependent soft-tissue mass in the attic (Prussak space) eroding the scutum and ossicles on CT, and restricting on non-EPI diffusion MRI — the MRI is what separates cholesteatoma from granulation tissue after surgery.
Orient first
- Pars flaccida cholesteatoma starts in Prussak space and erodes the scutum and the incus.
- Complications: lateral semicircular canal fistula, tegmen erosion, facial canal dehiscence, sigmoid sinus thrombosis.
- Non-EPI DWI detects residual or recurrent cholesteatoma ≥ 3 mm (verify local sensitivity).
Acquire the study
- High-resolution CT temporal bones, 0.5–0.6 mm, axial and coronal reformats, bone window.
The manoeuvre
- Coronal bone window: soft tissue in Prussak space with scutum blunting.
- Ossicles: erosion of the long process of the incus and the malleus head.
- Lateral semicircular canal: erosion of its bony roof (fistula).
- Tegmen tympani and facial nerve canal on coronal reformats.
What confirms it
- A soft-tissue mass with typical erosion on CT, or restriction on non-EPI DWI after surgery.
What licenses you to exclude it
- No restriction on non-EPI DWI makes recurrence ≥ 3 mm unlikely.
The classic misread
- Calling any opacification cholesteatoma — without erosion CT cannot separate it from fluid or granulation.