Zygomatic sialolithiasis diagnosed with computed tomography in a dog

Computed tomographic characteristics of normal salivary glands in dogs

Background

Various salivary gland diseases diagnosed on computed tomography (CT) in dogs have been reported. However, no study described the size and CT attenuation value of normal salivary glands in dogs.

Aim

This retrospective analytical study aimed to evaluate the size and attenuation value of the mandibular and zygomatic salivary glands on CT in dogs without cervical or head lesions.

Methods

The maximum cross-sectional area (MCSA) was measured in 96 dogs and attenuation value on non-contrast and postcontrast images were measured in 90 dogs. Dogs were divided into three groups based on body weight: group 1, ≤ 5.0 kg; group 2, 5.1-10.0 kg; and group 3, 10.1-15.0 kg.

Results

There were significant differences in MCSA for both glands among the three groups. There was no difference in MCSA between the left and right sides in both salivary glands. The MCSA for both salivary glands positively correlated with body weight (p < 0.001). There was a significant difference in the MCSA of the zygomatic gland between males and females (p = 0.02), but there was no significant difference in the mandibular gland. There was a significant difference in the attenuation value between the mandibular and zygomatic glands in non-contrast studies (p < 0.001), but there was no significant difference in postcontrast studies.

Conclusion

This study established the reference for the size and attenuation value of the mandibular and zygomatic glands in dogs and provided background data for future CT evaluation of dogs with salivary gland diseases.

Diagnostic Findings and Surgical Management of Three Dogs Affected by Osseous Metaplasia Secondary to a Salivary Mucocele

Saliva is an irritant of the subcutaneous tissue, thus causing the development of a non-epithelial reactive pseudocapsule. Metaplastic ossification of the pseudocapsule is a condition rarely described in the veterinary literature. The main causes of calcification are trauma, tumours, various chronic inflammatory conditions and fibrodysplasia ossificans progressiva. The aim of the present case series was to describe three dogs affected by a calcified salivary mucocele. The medical records of dogs affected by a cervical sialocele were retrospectively evaluated, and three cases met the inclusion criteria. All the dogs in this study were referred to the Veterinary Teaching Hospital (VTH) of the Department of Veterinary Sciences of the University of Turin (Turin, Italy) for a large solid mass in the intermandibular region. The diagnosis of a mucocele was confirmed clinically by centesis and by radiography or CT. Complete excision of both the pseudocyst and the ipsilateral mandibular/monostomatic sublingual salivary gland was performed in all cases. The histological report showed large areas of bone metaplasia within the pseudocapsule and chronic sialadenitis. Based on this limited case series, complete excision of the pseudocyst and a concurrent sialoadenectomy provided an effective treatment for this rare salivary mucocele disorder.

An Atypical Presentation of a Zygomatic Sialocele in a dog

A sialocele is an accumulation of salivary fluid due to leakage into the interstitial space surrounding the affected salivary gland and/or its corresponding duct. Reported causes of salivary leakage include trauma, foreign bodies, sialoliths, and neoplasia, but in many cases the etiology is not identified. Clinical signs of sialoceles associated with the zygomatic salivary gland or corresponding duct usually include exophthalmos due to periorbital salivary accumulation, whereas sialoceles associated with the mandibular or sublingual glands or ducts usually manifest as cervical, pharyngeal and/or sublingual salivary accumulation. This case report describes an atypical cervical presentation of a zygomatic sialocele in a dog that resolved after zygomatic sialoadenectomy.

Clinical and CT sialography findings in 22 dogs with surgically confirmed sialoceles

Sialoceles are an uncommon canine salivary gland disease, and complete surgical resection is important for a positive outcome. Radiographic sialography has been described as a diagnostic test for presurgical planning; however, superimposition artifacts may limit the diagnosis and detection of all affected glands. Computed tomographic (CT) sialography is a promising technique for delineating the salivary gland apparatus. The aims of this retrospective, observational study were to describe clinical and CT sialographic findings in a group of dogs with confirmed sialoceles, to determine the sensitivity of CT sialography for detecting affected salivary glands using surgery as the reference standard and to determine interobserver agreement for CT sialographic assessments. Dogs were included if they underwent a CT sialography study followed by surgical resection of the diseased gland(s) and histopathological analysis. Computed tomography sialography studies of dogs with surgically confirmed sialoceles (n = 22) were reviewed by a European College of Veterinary Diagnostic Imaging (ECVDI)-certified radiologist and an ECVDI resident. Interobserver agreement was calculated using Cohen's kappa statistics. CT sialography results were compared to surgical findings to determine sensitivity. Contrast leakage was detected in 12 of 22 dogs (54.5%), with intrasialocele leakage being most frequently observed (7/12, 58.3%). There was substantial agreement (κ = 0.70) between reviewers identifying diseased glands, substantial agreement (κ = 0.62) on the diagnostic quality, and no to slight agreement (к = 0.13) in the detection of contrast leakage. The overall sensitivity of CT sialography to detect surgically confirmed diseased glands was 66.7% (95% confidence interval: 48.8-80.8). In conclusion, these findings support the use of CT sialography as an adjunct diagnostic test for treatment planning in dogs with sialoceles.

Computed tomographic appearance of sialoceles in 12 dogs

Published findings on the computed tomographic (CT) appearance of sialoceles are limited to brief descriptions from reported cases in eight dogs and one cat. The authors have seen sialoceles with CT characteristics that are not consistent with these previous reports. The purpose of this multicenter, retrospective, descriptive, case series study was to provide more detailed descriptions of the CT appearance of confirmed sialoceles in dogs. Dogs over a 10-year period with cytologically or histologically confirmed sialoceles and pre- and postcontrast CT studies of the head were included. Multiple qualitative and quantitative features were described for each sialocele with histological correlation. Twelve dogs with a total of 13 sialoceles were identified, including: seven cervical sialoceles, three complex (combined cervical and sublingual) sialoceles, two sublingual sialoceles, and one zygomatic sialocele. All sialoceles were characterized by fluid attenuating, non-contrast enhancing contents (median 18.5 HU) and soft tissue attenuating, contrast-enhancing walls. The external margins of all sialocele walls were smooth; however, the internal margins in six sialoceles were irregular with poorly defined nodular to frond-like protrusions. Mineralized foci of variable size (range < 1 mm to 4.8 mm) and attenuation (range 119 to 1253 HU) were present in seven sialoceles and histologically identified as sialoliths (three sialoceles) and osseous metaplasia (two sialoceles). A unique finding in the sialoceles in this study was the presence of intraluminal nodular to frond-like protrusions arising from the wall. This study also reports the CT appearance of cervical and complex sialoceles and sialocele mineralizations.

Intracanalicular injection of N-acetylcysteine as adjunctive treatment for sialoceles in dogs: 25 cases (2000-2017)

OBJECTIVE

To describe intracanalicular injection of 10% N-acetylcysteine (IINAC) as adjunctive treatment for sialoceles in dogs.

ANIMALS

25 client-owned dogs.

PROCEDURES

Hard copy medical records at 2 veterinary ophthalmology practices were searched to identify dogs that underwent IINAC for treatment of sialoceles from January 2000 to December 2017. Signalment, affected salivary gland, clinical signs, duration of signs, other treatments administered, diagnostic tests performed, anesthetic approach, N-acetylcysteine volume administered, complications, follow-up time, and recurrence of sialoceles were recorded. Descriptive statistics were reported.

RESULTS

Boxers and mixed-breed dogs were most commonly represented. Subjectively decreased globe retropulsion and conjunctival or periorbital swelling (23/25 [92%] dogs each) were the most common clinical signs, with no vision deficits in any patient. The zygomatic gland was mainly affected (23/25 [92%] dogs), followed by parotid and mandibular glands (1 [4%] dog each). The condition was unilateral in 22 (88%) dogs. Ultrasonography (19/25 [76%] dogs), MRI (14 [56%]), fine-needle aspiration (20 [80%]), and biopsy (4 [16%]) were performed; however, the condition was deemed idiopathic in 22 (88%) dogs. Most IINACs were performed with local anesthesia (median volume, 5 mL/gland; range, 1.5 to 9 mL). No complications were identified. Other treatments included antimicrobials and anti-inflammatories. Mean follow-up time was 18.8 months. All recurrences (5/23 [22%] dogs) were controlled with medical management.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested noninvasive IINAC may be a useful adjunctive treatment for sialoceles in dogs. The procedure was easily and safely performed with local anesthesia (or general anesthesia with concurrent diagnostic imaging) in these dogs.

Sialocoele associated with the molar salivary gland in a British Shorthair cat

Case summary

A 16-year-old neutered female British Shorthair cat presented with a 5-year history of swelling lateral to the left mandible that intermittently discharged viscous, clear fluid from a small defect in the skin. CT, ultrasonography, physical characteristics and cytology of the fluid were suggestive of sialocoele. CT showed a large, cavitary, fluid-filled mass lateral to the left mandible. A ventral approach was used to resect the left mandibular, sublingual and molar salivary glands and sialocoele. Histopathology of the molar and mandibular and sublingual glands showed chronic active sialoadenitis with more severe changes in the molar gland. There were no signs of recurrence of the sialocoele 12 months after surgery.

Relevance and novel information

This is the first report of a cranial cervical sialocoele potentially involving the molar salivary gland in a cat. Resection of the mandibular, sublingual and molar salivary glands should be considered in cats that present with a cranial cervical sialocoele.

Comparison of three surgical approaches for zygomatic sialoadenectomy in canine cadavers

Objective

To compare three surgical approaches for excision of the zygomatic gland in dogs.

Study design

Cadaveric study.

Animals

Cadavers of mesocephalic dogs (n = 20).

Methods

Each skull was assigned to a lateral approach with zygomatic arch ostectomy on the left (n = 20) and one approach without ostectomy on the right, ventral (n = 10) or dorsal (n = 10) to the zygomatic arch. Approaches were evaluated for surgical exposure (rated on a scale of 1‐5 with one optimal exposure), tissue trauma, and completeness of gland removal. Glands from each side were weighed to compare as internal control.

Results

The ostectomy‐based approach offered excellent surgical view and good exposure of the zygomatic gland but caused more tissue trauma. The dorsal nonostectomy approach did not allow complete zygomatic gland extraction in nine of the 10 dogs, whereas the ventral nonostectomy approach enabled complete extraction in all 10 dogs.

Conclusion

The ventral zygomatic approach allowed complete removal of the zygomatic gland, with good surgical overview, while reducing tissue trauma and preserving the zygomatic arch.

Clinical significance

The ventral nonostectomy approach should be considered as an alternative to excise the zygomatic gland in dogs.

A Novel Technique for Partial V-shaped Zygomatic Arch Ostectomy for Excision of Zygomatic Salivary Glands in Dogs

The present study described a novel technique for a partial V-shaped ostectomy of the zygomatic arch (ZA) for surgical excision of the zygomatic salivary glands (ZSG) in dogs and addressed advantages and disadvantages related to this procedure. The study was conducted on 6 clinically healthy mongrel dogs. A 3-4 cm curvilinear transcutaneous incision was performed parallel to the dorsal margin of the ZA. An additional 2 cm vertical incision was performed perpendicular to the former one forming a T-shaped incision over the ZA. The skin, subcutaneous tissue, and periosteum over the ZA were dissected and reflected laterally. At 0.5 cm from the orbital ligament, a V-shaped segment from the ZA was resected using an electrical saw. The base of the V-shaped segment was 1.5 cm wide and its apex was 0.5 cm from the ventral margin of the ZA. A combination of sharp and blunt dissection was used to dissect and excise the ZSG from the surrounding tissues. The periosteal flaps were coaptated in a simple continuous pattern. The subcutaneous tissue and skin were closed as usual. The new approach was a feasible technique for the excision of the ZSGs without considerable postoperative complications in dogs. The novel V-shaped partial ostectomy of the ZA technique is reliable, satisfactory, and relatively less invasive for surgical excision of ZSGs in dogs. Further work should be conducted on clinical cases.

Sublingual sialocele in a cat

Case summary

A 1-year-old male neutered cat was presented with a right-sided swelling of the floor of the oral cavity, causing dysphagia and hypersialorrhoea for 2 months. Fine-needle aspiration of the mass and CT were suggestive of a right sublingual sialocoele with no obvious cause. Surgical resection of the ipsilateral sublingual–mandibular salivary gland complex, as well as marsupialisation of the mucocoele, was performed. The cat recovered uneventfully. Histopathological examination of the resected specimen confirmed the diagnosis. No sign of recurrence was reported 7 months after surgery.

Relevance and novel information

Overall, sialocoeles are rare in cats but sublingual mucocoele is the most common form. Diagnosis is usually straightforward and the use of CT to help localise the affected site and possibly identify a cause has been infrequently described. Surgical treatment recommendations have been updated, which also makes a refresher of this uncommon condition likely to be of interest to the feline practitioner.

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

A case of exophthalmos due to zygomatic mucocele in a puppy with ipsilateral segmental maxillary atrophy is reported. A 7-month-old, mixed breed, male dog suffered the sudden-onset of unilateral painful exophthalmos and a gradual swelling of the right temporal region. A compressing, right retrobulbar mass was observed by ultrasound. Computed tomography revealed a large multiloculated cyst-like lesion of the right zygomatic gland projecting into the orbital space, thus displacing the eyeball. The ipsilateral molar part of the maxillary bone was underdeveloped, besides showing crowded, abnormal, multiple, unerupted maxillary molar teeth in the caudal maxillary region. Modified lateral orbitotomy and a selective caudal maxillary bone access were performed. The cyst-like lesion was removed and the zygomatic gland and the wall was collected for histology, which confirmed the mucocele. Clinical and imaging examinations six months after surgery showed neither recurrence of the mucocele nor ocular abnormalities. A possible common pathogenic mechanism involving these two conditions could be hypothesized.

Clinical, computed tomographic, magnetic resonance imaging, and histologic findings associated with myxomatous neoplasia of the temporomandibular joint in two dogs

CASE DESCRIPTION A 15-year-old neutered female mixed-breed dog (dog 1) and an 11-year-old neutered female Labrador Retriever (dog 2) were examined because of unilateral exophthalmus, third eyelid protrusion, and periorbital swelling that failed to respond to antimicrobial treatment. CLINICAL FINDINGS Both dogs underwent ultrasonographic, CT, and MRI examination of the head. In both dogs, advanced imaging revealed a poorly defined, peripherally contrast-enhancing, mucous-filled cystic mass that radiated from the temporomandibular joint and infiltrated the periorbital tissues and retrobulbar space. Both dogs underwent surgical biopsy of the periorbital mass. A viscous, straw-colored fluid was aspirated from the retrobulbar region in both dogs. The initial histologic diagnosis for dog 1 was zygomatic sialadenitis and sialocele. However, the clinical signs recurred, and histologic examination of specimens obtained during a second surgical biopsy resulted in a diagnosis of myxoma. The histologic diagnosis was myxosarcoma for dog 2. TREATMENT AND OUTCOME In both dogs, clinical signs recurred within 2 weeks after surgery and persisted for the duration of their lives. Dog 1 received no further treatment after the second surgery and was euthanized 34 months after initial examination because of multicentric lymphoma. Dog 2 was treated with various chemotherapy agents and was euthanized 11 months after initial examination because of a dramatic increase in periocular swelling and respiratory stertor. CLINICAL RELEVANCE Temporomandibular myxomatous neoplasia can be confused with zygomatic sialocele on the basis of clinical signs but has characteristic MRI features. Representative biopsy specimens should be obtained from areas close to the temporomandibular joint to avoid misdiagnosis.

Ultrasound and multidetector computed tomography of mandibular salivary gland adenocarcinoma in two dogs

Malignant tumors of the salivary glands are rare in dogs, with adenocarcinoma being the most represented. Parotid and mandibular glands are most commonly affected in dogs. Because of local invasivity and high metastatic potential, preoperative imaging evaluation of mandibular region and tumoral staging is essential along with biopsy sampling. The present manuscript describes the ultrasound and computed tomographic imaging findings of mandibular gland adenocarcinoma in two dogs and discusses their clinical utility.