MRI of a middle ear cholesteatoma in a cat.

A 9-year-old Maine coon cat presented with right-sided Horner and facial nerve paralysis. Magnetic resonance imaging (MRI) showed a heterogeneously contrast-enhancing mass occupying the right dorsolateral compartment of the tympanic cavity and extending into the ventromedial compartment, which was expanded and fluid filled. A ventral bulla osteotomy was performed to debulk the soft tissue mass. Histopathology revealed a cholesteatoma. The cat showed slow improvement of clinical signs and was euthanized eleven months postoperatively for unrelated causes. The MRI characteristics of middle ear cholesteatoma in the present case varied from those described in humans and dogs.