Modified lateral orbitotomy for vision‐sparing excision of a zygomatic mucocele in a dog

Abstract

A 1-year-old Shar Pei presented for recent-onset exophthalmos and right peri-ocular facial swelling. Physical examination revealed the facial mass was of soft-tissue consistency and nonpainful to the dog. Due to inability to retropulse the globe during ophthalmologic examination, it was suspected the mass had impinged into the orbit, resulting in rostral displacement of the globe. Anatomic location suggested the lesion was probably associated with the zygomatic salivary gland. Fine-needle aspiration and subsequent cytological evaluation of fluid extracted from the facial mass was consistent with a diagnosis of zygomatic mucocele. Computed tomography imaging confirmed a single fluid-filled mass was resulting in both the facial distention and the exophthalmos. A modified, lateral orbitotomy surgical approach was selected for excision of the lesion to provide ventral exposure to the orbit, while minimizing trauma to the globe and supporting structures. Histopathology of the excised lesion confirmed a diagnosis of zygomatic mucocele. This case demonstrates utilization of a modified lateral orbitotomy for effective surgical management of a zygomatic mucocele in a dog, with preservation of vision and absence of any significant postoperative complications.

Three‐dimensional printing of orbital and peri‐orbital masses in three dogs and its potential applications in veterinary ophthalmology

“…Although not as hard as bone, it can be used to identify and practice osteotomy and ostectomy sites as well as contour metallic orthopedic implants prior to surgery. 3,4,7 Pertinent to the cases discussed in this report, there are multiple described techniques for the orbitotomy procedure in dogs, [29][30][31][32][33] and some of these, such as the modified lateral 29 and transfrontal 32 approach, require performing an osteotomy at multiple sites. Therefore, identifying and practicing the optimal surgical approach can decrease patient morbidity, surgical time, and surgical errors.…”

What Is Your Diagnosis?

“…5 Ultrasonography, CT, and magnetic resonance imaging are considered the best imaging modalities for evaluating orbital disease. 2 Ultrasonography is beneficial in compromised patients because it does not require anesthesia, and it is the least expensive imaging modality. 6 Both CT and magnetic resonance imaging are superior to ultrasonography in evaluating extent of the lesion and assessing adjacent soft tissues and bony structures.…”

“…Mucoceles, while rare in dogs, are one of the most frequently diagnosed salivary gland disorders. 2 They occur when saliva leaks from the zygomatic salivary gland into the surrounding tissues causing inflammation and tissue fibrosis. 2,3 The cystic structure is normally lined by granulation or fibrous tissue.…”

“…2,3 The cystic structure is normally lined by granulation or fibrous tissue. 2 Dogs with zygomatic mucoceles may have clinical signs of orbital swelling, exophthalmos, protrusion of the third eyelid, protrusion of the oral mucous membrane behind the last upper molar, and protrusion of a mass beneath the conjunctiva. [3][4][5] Previous trauma is often reported with zygomatic mucoceles 4,5 ; however, there was no history of trauma in the dog of this report.…”

Exophthalmos associated to orbital zygomatic mucocele and complex maxillary malformation in a puppy

“…Despite the variable underlying causes, the clinical signs of these various conditions are very similar to one another. Diagnostic imaging can be useful to differentiate a zygomatic gland disease from other orbital diseases (Penninck et al, 2001;Bartoe et al, 2007;Boston, 2010;Lee et al, 2014). Cases of zygomatic mucocele were reported in a cat and in a ferret (Miller and Pickett, 1989;Speakman et al, 1997).…”