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.

Surgical treatment of middle ear cholesteatoma using an oral approach in 2 dogs.

Middle ear cholesteatoma is caused by the formation of epidermoid cysts that result in distention and enlargement of the tympanic bulla with subsequent destruction of surrounding tissues. We report treatment of middle ear cholesteatoma in 2 dogs, via an oral surgical approach. Abnormal tympanic bulla contents and the wall compressing the pharynx were successfully removed in both cases. Computed tomography imaging, surgical findings, and histopathology results were consistent with middle ear cholesteatoma in both cases. The outcomes in both cases suggest that an oral surgical approach may be an alternative treatment for middle ear cholesteatoma in dogs. Key clinical message: Despite the limited number of cases described herein, our report indicates that the direct oral approach for canine cholesteatoma may be and alternative approach.

Traitement chirurgical du cholestéatome de l'oreille moyenne par approche orale chez deux chiens. Le cholestéatome de l'oreille moyenne est causé par la formation de kystes épidermoïdes qui entraînent une distension et l'élargissement de la bulle tympanique avec destruction subséquente des tissus environnants. Nous rapportons le traitement d'un cholestéatome de l'oreille moyenne chez deux chiens, via une chirurgie par approche buccale. Le contenu anormal de la bulle tympanique et la paroi comprimant le pharynx ont été enlevés avec succès dans les deux cas. L'imagerie par tomodensitométrie, les résultats chirurgicaux et les résultats histopathologiques étaient compatibles avec un cholestéatome de l'oreille moyenne dans les deux cas. Les résultats dans les deux cas suggèrent qu'une approche chirurgicale orale peut être un traitement alternatif pour le cholestéatome de l'oreille moyenne chez le chien.Message clinique clé :Malgré le nombre limité de cas décrits ici, notre rapport indique que l'approche orale directe pour le cholestéatome canin peut être une approche alternative.(Traduit par Dr Serge Messier).

Clinical analysis and nonsurgical management of 11 dogs with aural cholesteatoma.

BACKGROUND: Aural cholesteatomas, also called tympanokeratomas, are destructive and expansile growths of keratinizing epithelium that develop in the middle ear. They have been reported sporadically in dogs, and surgery is usually the recommended treatment. OBJECTIVES: To describe the common clinical, radiological and histological findings of cholesteatoma; to report on the outcome of conservative management. ANIMALS: Eleven dogs (13 ears) with cholesteatomas. METHODS AND MATERIALS: Medical records were reviewed for dogs diagnosed with cholesteatoma between 2012 and 2018. All dogs had computed tomography (CT) and/or magnetic resonance imaging (MRI) followed by trans-canal endoscopic procedure (TEP) for removal and biopsy of middle ear lesions. Dogs were then treated with in-clinic flushing initially weekly tapered to monthly, as well as at-home ear cleaning and application of topical otic steroid medication, initially daily then tapered to once or twice weekly. RESULTS: Nine dogs had a history of chronic otitis externa; head tilt or facial paralysis was present in seven and four cases, respectively. Otic examination identified a protruding nodule in seven ears. CT demonstrated soft tissue-like material in 12 bullae and expansion in seven bullae. MRI revealed minimally contrast-enhancing bulla contents in 12 ears. Post-TEP and with maintenance medical treatment, nine ears had no further signs of middle ear disease during a mean follow-up of 27.9 months. CONCLUSIONS AND CLINICAL IMPORTANCE: The results suggest that otitis externa may not necessarily precede cholesteatoma in all dogs. MRI appears to be more sensitive than CT for identifying cholesteatomas. Conservative treatment of cholesteatomas could be useful before or as an alternative to surgery.

Diagnosis and Management of Cholesteatomas in Dogs.

Surgical intervention of aural cholesteatomas in dogs can be curative. Imaging findings include a soft tissue density in the middle ear and destruction of the bone of the bulla with characteristics of an aggressive lesion. Dogs with early stage disease have a better outcome than those with chronic disease, temporal bone involvement and neurologic signs. Dogs with recurrent disease can be reoperated or managed medically with long-term resolution or palliation of clinical signs.

Canine aural cholesteatoma: a histological and immunohistochemical study.

Canine aural cholesteatoma is an epidermoid cyst that forms in the middle ear cavity as a rare complication of otitis media but the aetiopathogenesis remains controversial. In the present study, 13 cases of canine aural cholesteatoma were investigated histologically and immunohistochemically and compared with cases of chronic otitis. The immunohistochemical investigation was performed using the following monoclonal antibodies: anti-cytokeratins (CK) 14, 16, 8/18, and 19, and anti-Ki67. The proliferative indexes (PIs) of cholesteatomata and otitis epithelium were calculated as the percentage of Ki67 positive nuclei/total nuclei. Histologically, the cholesteatomata were composed of a hyperplastic, hyperkeratotic epithelium (matrix) resting on a fibrous perimatrix, infiltrated by inflammatory cells and devoid of cutaneous adnexa. Immunohistochemically, the cholesteatoma epithelium was CK14- and CK16-positive, and CK8/18- and CK19-negative. A similar pattern of CK expression was found in otitis externa. In otitis media, ciliated epithelium stained CK8/18- and CK19-positive in all layers, CK14-positive in the basal layers, and CK16-negative. The mean PIs in cholesteatomata and otitides were 18.8 and 17.8, respectively. The immunohistochemical pattern of CK expression in cholesteatomata, when compared with chronic otitis, was suggestive of hyperproliferative epithelium, but its origin could not be demonstrated. Comparable PI values were obtained in cholesteatoma and in chronic otitis, which confirmed that Ki67 is a valuable indicator of a hyperproliferative state, but not a predictor of aggressiveness.

MRI findings of a middle ear cholesteatoma in a dog.

This article describes the MRI features of a middle ear cholesteatoma in an 8 yr old flat-coated retriever. Physical examination revealed pain on opening the jaw, and otoscopic examination showed tympanic membrane rupture associated with hyperplastic tissue at the entrance of the middle ear. Standard MRI sequences allowed for the identification of a severely expanded bulla containing material that was isointense to brain tissue on T1-weighted images and of mixed intensity on T2-weighted and fluid-attenuated inversion recovery sequences. No postcontrast enhancement of the content was present, but the lining of the bulla was partially enhanced. The images allowed evaluation of the surgical margins and the secondary changes due to the expansion of the mass. Surgery was performed and histopathology confirmed the presumptive diagnosis of cholesteatoma. In the present case, MRI appeared to serve as a good alternative to computed tomography for the diagnosis of cholesteatoma.

Cholesteatoma after lateral bulla osteotomy in two brachycephalic dogs.

This report describes a French bulldog and a pug that presented to the authors' hospital following total ear canal ablation (TECA) and lateral bulla osteotomy (LBO), with signs of recurring otitis media and difficulty opening their mouths. The bulldog also had unilateral facial paralysis and sensory deficits of the trigeminal nerve on the ipsilateral side. Computed tomography and MRI scans suggested cholesteatoma in the bulldog, but showed only slight enlargement of the bulla in the pug. Histopathologic examination of samples yielded cholesteatoma in both cases. The authors suspect that development of the cholesteatomas was linked to the TECA/LBO surgery in both cases. Cholesteatomas may occur more frequently than currently thought. Even if only slight changes of the bulla wall are detected on CT, early-stage cholesteatoma should be considered. The narrow anatomic conditions in brachycephalic dogs possibly predispose such breeds to develop cholesteatoma after middle ear surgery because complete removal of all inflammatory and epithelial tissue can be more difficult than in other breeds. To the authors' knowledge, this is the first report of an aural cholesteatoma causing sensory deficits of the trigeminal nerve.

Middle ear cholesteatoma in 11 dogs.

Middle ear cholesteatoma is a rare condition in dogs with chronic otitis. Otorrhea, otodinia, and pain on temporomandibular joint palpation are the most common clinical signs. Neurological abnormalities are often detectable. Computed tomography reveals the presence of an expansive and invasive unvascularized lesion involving the tympanic cavity and the bulla, with little or no contrast enhancement after administration of contrast mediu. Video-otoscopy may detect pearly growth or white/yellowish scales in the middle ear cavity. Surgery is the only therapy but is associated with a high risk of recurrence.

Computed tomography features of middle ear cholesteatoma in dogs.

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.

Aural cholesteatoma in twenty dogs.

OBJECTIVE: To determine the clinical course in dogs with aural cholesteatoma. STUDY DESIGN: Case series. ANIMALS: Dogs (n=20) with aural cholesteatoma. METHODS: Case review (1998-2007). RESULTS: Twenty dogs were identified. Clinical signs other than those of chronic otitis externa included head tilt (6 dogs), unilateral facial palsy (4), pain on opening or inability to open the mouth (4), and ataxia (3). Computed tomography (CT) was performed in 19 dogs, abnormalities included osteoproliferation (13 dogs), lysis of the bulla (12), expansion of the bulla (11), bone lysis in the squamous or petrosal portion of the temporal bone (4) and enlargement of associated lymph nodes (7). Nineteen dogs had total ear canal ablation-lateral bulla osteotomy or ventral bulla osteotomy with the intent to cure; 9 dogs had no further signs of middle ear disease whereas 10 had persistent or recurrent clinical signs. Risk factors for recurrence after surgery were inability to open the mouth or neurologic signs on admission and lysis of any portion of the temporal bone on CT imaging. Dogs admitted with neurologic signs or inability to open the mouth had a median survival of 16 months. CONCLUSIONS: Early surgical treatment of aural cholesteatoma may be curative. Recurrence after surgery is associated with advanced disease, typically indicated by inability to open the jaw, neurologic disease, or bone lysis on CT imaging. CLINICAL RELEVANCE: Presence of aural cholesteatoma may affect the prognosis for successful surgical treatment of middle ear disease.

Removal of a cholesteatoma in a dog, using a caudal auricular approach.

A new surgical method for treating cholesteatoma in dogs is described. Although rarely reported in dogs, cholesteatomas may be more common than previously believed. Complete excision of a cholesteatoma is associated with low recurrence and good long-term prognosis. Surgical intervention, with total ear canal ablation and lateral bulla osteotomy, has been recommended in dogs with tumors of the middle ear; however, this technique often results in conductive hearing loss. Through a caudal auricular approach to the tympanic bulla, we were able to preserve the external ear canal, reconstruct the auditory ossicles, and graft the tympanic membrane. Results of brain stem auditory-evoked response tests in the dog revealed intact conduction potentials. A caudal auricular approach to the tympanic bulla is technically possible, preserves normal appearance, and may maintain, or even improve, hearing conduction of affected ears in dogs.