Cholesterol Granuloma Associated with Otitis Media and Destruction of the Tympanic Bulla in a Dog

Abstract

Abstract. An 8-year-old, male neutered Irish Setter was presented with a 2-week history of pain upon opening the mouth and chronic otitis externa. Computed tomography examination revealed destruction of the left tympanic bulla with a soft-tissue density within the remains of the tympanic cavity. Cytology of aspirates collected from tissue adjacent to the tympanic bulla revealed suppurative inflammation and bacteria. A ventral bulla osteotomy was performed. Histopathology of granulation tissue within the remains of the tympanic cavity was diagnostic of cholesterol granuloma.Key words: Cholesterol granuloma; computed tomography; dogs; histopathology; middle ear; otitis media.Cholesterol granuloma (CG) is a granulomatous lesion containing cholesterol crystals. 4 In humans, CG frequently develops in the middle ear or mastoid region. 3In the middle ear, CG is usually associated with chronic otitis media; however, it may also be associated with adenomatous tumors and endolymphatic sac tumors in this location. 4,13 Cholesterol granulomas have also been reported in the petrous apex, maxillary sinus, frontal sinus, orbit, breast, tunica vaginalis, peritoneum, brain, and kidney of humans. 4,7,9 In domestic animals, there are reports of CG in the brain of the horse, 8 the middle ear, the maxilla and brain of the dog, 2,10,12 and the uterus and brain of the cat. 5,14 This report describes a canine case of CG that is associated with otitis media and destruction of the tympanic bulla.An 8-year-old, 36.6-kg, male neutered Irish Setter was referred with a 2-week history of lethargy, anorexia, difficulty chewing, and pain upon opening the mouth. Additionally, there had been a 2-year history of intermittent otitis externa on the left. Physical examinations by the referring veterinarian in the 2 weeks prior to referral revealed pain and swelling in the left submandibular region, pain upon opening the mouth, and brown exudate in the left horizontal ear canal. A mixed population of bacterial cocci and rods were present on cytologic examination of the exudate. Treatment with oral meloxicam and cephalexin resulted in some clinical improvement, and the dog was referred for further evaluation.On examination at the University of Melbourne Veterinary Clinic and Hospital, there was discomfort upon opening the mouth; however, pain, swelling, atrophy, and asymmetry were not detected upon palpation of the head and masticatory muscles. The left horizontal external ear canal was narrowed and inflamed; a moderate volume of brown exudate in the canal prevented visualization of the tympanic membrane. The rectal temperature was normal, and the remainder of the physical examination was unremarkable. At this time, differential diagnoses for the pain upon opening the mouth included temporomandibular joint disease, masticatory myositis, otitis media, migrating foreign body, and retrobulbar disease.Results of a preanesthetic blood analysis were normal, and the dog was anesthetized for further diagnostic tests. Electromyography was performed on the tempo...

Aural Cholesteatoma in Twenty Dogs

“…Included within these 7 cases were those that were not clinically localized and had stratified squamous epithelium and adnexa present in the biopsy but no ciliated respiratory epithelium to histologically confirm localization to the middle ear. [17][18][19][20] Twenty cases including the case confirmed by aspirate cytology met the inclusion criteria; 14 specimens had ciliated respiratory epithelium and 6 were confirmed to be from the middle ear by sample labeling and surgical record data only. Nineteen cases had histologic samples available and could be localized to the middle ear; 16 of these cases had biopsies that contained all 3 histologic criteria of a cholesteatoma including metaplastic stratified squamous epithelium, cornification and accumulation of cornified material, whereas 3 cases, and the case with cytology only, had samples of the central lesion contents and had 2 of 3 criteria (presence of cornification and accumulation of cornified material; Fig 1).…”

Transoral approach for ventral tympanic bulla osteotomy in the dog: A descriptive cadaveric study*

“…Our results support the clinical application of this transoral approach to the tympanic bulla. This approach would be relevant to treat middle ear disease, such as otitis media, with or without otitis interna, inflammatory polyps, cholesteatoma, and cholesterol granuloma, as long as the simultaneous approach of the ear canal is not needed. According to veterinary literature, there is a high discordance (89.5% of cases) between microbial sampling from the external ear canal and the actual microbial flora of the middle ear .…”

“…Total ear canal ablation combined with lateral or ventral bulla osteotomy is the treatment of choice for combined end‐stage otitis externa and media in the dog . A lateral or ventral approach to the tympanic bulla can be used to treat aural cholesteatomas, tumors of the middle ear, inflammatory polyps, cholesterol granulomas of the middle ear, as well as primary secretory otitis media (PSOM) of the Cavalier King Charles spaniel …”

Computed Tomography Features of Middle Ear Cholesteatoma in Dogs

“…CT was performed in one of the two dogs with middle ear cholesterol granuloma. There was lysis of the tympanic bulla without expansion, presence of nonenhancing material isoattenuating to brain in the tympanic cavity, swelling, and contrast enhancement of the soft tissues immediately lateral and ventral to the tympanic bulla 21 . The dog with coexisting cholesterol granuloma and cholesteatoma had only hyperattenuating middle ear material 8…”

“…Cholesterol granuloma has been associated with a middle ear cholesteatoma in one dog and as the only middle ear disease in two dogs 8,20,21 . CT was performed in one of the two dogs with middle ear cholesterol granuloma.…”