Bilateral cholesterol granulomas in the middle ear cavities of a cat with sinonasal disease successfully removed via video-otoscopy

Abstract

CASE DESCRIPTION A 9-year-old spayed female Maine Coon cat was presented at the University of Veterinary Medicine Vienna for further investigation of chronic nonpruritic bilateral ear disease and unilateral Horner syndrome. CLINICAL FINDINGS Physical examination and otoscopy findings included right sided Horner syndrome, a right head tilt of approximately 20° and a small pink nodule in the right and several smaller nodules in the left proximal horizontal external ear canal. Computed tomography and magnetic resonance imaging revealed soft tissue opacity material in both middle ear cavities, the caudal portion of the nasal cavity, the left nasopharyngeal meatus and the right frontal sinus. Via videootoscopy, 2 multilobular and several flat nodules were detected in the proximal right horizontal external ear canal and in the left tympanic bulla, respectively. Histopathological examination confirmed the diagnosis of cholesterol granulomas. TREATMENT AND OUTCOME All otic cholesterol granulomas (CGs) were removed via video-otoscopy (VO), and topical treatment was initiated in addition to oral prednisolone. After the histopathological confirmation, negative microbial cultures from the middle ear cavities, and the remission of the symptoms by the first recheck, topical, and systemic treatment were discontinued. A follow-up 6 months later, did not reveal any recurrence of the CGs. CLINICAL RELEVANCE To our knowledge, this is the first case of bilateral CGs diagnosed with a combination of CT, MRI, VO, and histopathology and removed minimal invasively via VO, without a need for ventral bulla osteotomy, which led to complete remission of all signs and no relapse until the follow up 6 months later.

Imaging findings in otitis media and resulting secondary lesions in dogs and cats – an image essay

“…CT findings [45,[47][48][49] ▪ Central soft-tissue dense, well-defined, expansile masses with absence or minimal contrast enhancement, without an internal matrix, septation or mineralization ▪ Enhancement of the periphery of the lesion and of adjacent soft tissues structures may be seen ▪ Lesion associated with cortical thinning and trabecular erosion MRI findings [46][47][48]50] Overall, the signal behavior of aural cholesterol granuloma is variable depending on the protein content, the phase of blood products and the extent of underlying granulation. t1w pre contrast and t2w: typically, high signal due to the presence of methemoglobin, proteinaceous debris, and cholesterol in the center, distinct hypointense peripheral rim on T2-weighted images due to the presence of hemosiderin and connective tissue t1w post contrast (gadolinium): no contrast enhancement in the center, faint peripheral enhancement due to inflammatory response (difficult to see because of the high T1 signal, subtraction improves visibility) fat suppression: remain high signal or in the presence of high content of cholesterol suppression of the fat signal In cases of coexisting lesions, such as inflamed granulation tissue, cholesteatoma and cholesterol granuloma, the possibilities for classifying changes based on morphological characteristics are limited [51].…”

Cholesterol granuloma in the choroid plexus of a cat

“…Cholesterol granulomas in cats and dogs most frequently occur in the middle ear because of chronic inflammation [ 18 – 22 ]. Intracranial cholesterol granuloma represents a rare finding in cats [ 4 , 12 – 15 ].…”