Computed Tomography Features of Middle Ear Cholesteatoma in Dogs

Abstract

We describe the computed tomography (CT) findings in 11 dogs with middle ear cholesteatoma. The cholesteatoma appeared as an expansile tympanic cavity mass with a mean attenuation value of 55.8 +/- 4.2 Hounsfield units. There was no appreciable contrast enhancement of the tympanic bulla contense but ring enhancement was seen in four dogs. Due to the slow progressive growth, the lesion causes severe bone changes at the contour of the tympanic bulla, including osteolysis, osteoproliferation and osteosclerosis, expansion of the tympanic cavity, and sclerosis or osteoproliferation of the ipsilateral temporomandibular joint and paracondylar process. Cholesteatoma can cause lysis of the petrosal part of the temporal bone, leading to intracranial complications. Although not definitive, CT provides useful information for distinguishing a middle ear cholesteatoma from otitis media and neoplasia. In otitis media, enlargement of the tympanic cavity is not routinely observed. In tumors that primarily affect the middle or inner ear, the predominant signs are lysis of the contour of the tympanic bulla or the petrosal part of the temporal bone, soft tissue swelling around the middle ear and marked contrast enhancement. In tumors that arise from the external ear, a soft tissue mass is visible within the external acusticus meatus, and the middle ear is only involved secondarily.

Clinical analysis and nonsurgical management of 11 dogs with aural cholesteatoma

“…Computed tomography scanning plays an important role in the assessment of dogs with middle ear diseases . It has been proposed that a nonenhancing but expansile lesion, which is hyper‐attenuating to brain, is likely to be a cholesteatoma . However, expansion of the bulla is not regularly observed .…”

“…Computed tomography (CT) and magnetic resonance imaging (MRI) are considered to be reliable methods for evaluating the middle ear and demonstrating middle ear‐related lesions . CT is utilized to better define bony structures and can yield valuable information for the detection of cholesteatoma . MRI is used for more accurate assessment of soft tissue structures and can be a useful tool for the further characterization of soft tissue changes and recognition of potential complications; however, it is not routinely utilized in part because of the relatively high cost.…”

“…To the best of the authors’ knowledge, 15 reports (covering a total of 70 cases) of canine cholesteatoma have been published . Reports in which the diagnosis of cholesteatoma was confirmed by histopathological evaluation in combination with CT and MR imaging are limited .…”

Computed tomographic features of clinical and subclinical middle ear disease in domestic rabbits (Oryctolagus cuniculus): 88 cases (2007–2014)

“…25,32,33 One limitation of the present study and the one by Jeklova et al 14 was that the imaging abnormalities of the middle ear were not confirmed during surgery, by histologic evaluation, or during necropsy. 20,36 Within the middle ear of rabbits, neoplasia, polyps, and cholesteatoma have not been reported. 25 The prevalence of CT-detected changes of the middle ear in the group 2 rabbits of the present study was 27%.…”

Traumatic tympanic bulla fracture

“…, Travetti et al . ). Traumatic ear injuries, excluding the pinna, in dogs are uncommon, and have been reported to occur at the junction of the auricular and annular cartilage, or by separation of the horizontal canal from the external auditory meatus (McCarthy et al .…”