Page 46 - Atlas of Small Animal CT and MRI

Figure 1.2.13 Cholesteatoma with Otitis Interna (Canine) MR

(a) T1, TP (b) T2, TP (c) T1+C, TP

(d) T1+C, DP (e) T1+C, SP
7y FS French Bulldog with head tilt. There is a well‐demarcated expansile mass emanating from the left tympanic bulla, which has eroded
the petrous temporal bone and adjacent occipital bone, extends into the cranial vault, and has resulted in brainstem deformation. The
mass is heterogeneous but T1 hypointense and moderately T2 hyperintense. There is irregular peripheral contrast enhancement (c: small
arrows) and adjacent meningeal enhancement (c–e: large arrow). Similar signal changes are noted in the right tympanic bulla but are
confined within the bulla cavity. Pronounced left‐sided temporal, masseter, and pterygoid muscle atrophy is also evident. Biopsy revealed
neutrophilic inflammatory response with abundant keratin‐like debris consistent with cholesteatoma.

Figure 1.2.14 Ceruminous Adenoma—External Ear (Feline) CT

8y MC Domestic Shorthair with unilateral
otitis externa. A well‐delineated contrast‐
enhancing mass is seen within the horizontal
part of the right external ear canal on con-
trast‐enhanced images (a,b: arrow). Fluid is
entrapped between the tympanic membrane
and the mass in the proximal part of the
canal (a: arrowhead). Thickening of the ipsi-
lateral tympanic bulla and a small volume of
exudate adherent to the bulla wall are sug-
gestive of previous otitis media. Excisional
biopsy revealed ceruminous adenoma of the
external ear canal and chronic otitis externa.

(a) CT+C, TP (b) CT+C, TP

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