Salivary gland disease in dogs and cats: 245 cases (1985-1988)

Diagnostic pathology records spanning 41 months (July 1985 through November 1988) were searched for diagnoses of salivary gland disease in dogs and cats. Review of 87,392 records from that period revealed 245 cases (0.3%) in which salivary gland tissue had been evaluated. During that period, salivary gland tissue was submitted to the laboratory almost twice as often from dogs (160 cases) as from cats (85 cases). On the basis of histologic examination, 89% of salivary gland submissions from small animal practices were allotted to 1 of 5 major categories: malignant neoplasms (30%; 74/245), sialadenitis (26%; 64/245), normal salivary gland (16%; 40/245), sialocele (9%; 21/245), and salivary gland infarction (8%; 20/245). The remaining 11% of submissions included various degenerative or fibrotic lesions, ductal ectasia, sialolithiasis, edema, benign neoplasia, and secondary salivary involvement with systemic or cervical lymphosarcoma or with fibrosarcoma in the head and neck.     

Feline necrotising sialometaplasia: a report of two cases

Unilateral swelling of submandibular salivary gland in two cats was diagnosed as necrotising sialometaplasia. Histological features that differentiate the disease from other salivary gland lesions, particularly neoplasia are: lobular necrosis of salivary tissue; squamous metaplasia conforming to duct and/or acinar outlines; preservation of salivary lobular morphology; and variable inflammation and granulation tissue.     

Salivary gland basal cell adenocarcinoma: a report of cases in a cat and two dogs

Basal cell adenocarcinoma of the salivary gland is described in a cat and two dogs; tumour tissue was characterized by cords and islands of epithelial cells with a distinct basal layer. The tumours were stained by various immunohistochemical methods. In addition to positive staining with cytokeratin 14 and pancytokeratin (CKs 5, 6, 8, 17 and 19), there was also staining with Jack bean agglutinin A (ConA) and soya bean agglutinin (SBA); this occurs in many other types of salivary gland tumours and is a feature of normal salivary gland acinar cells. In one dog there was also staining with SBA. This is the first report of this tumour in domestic animals; the immunohistochemical characteristics did not distinguish it from other salivary gland tumours.     

Oncocytoma in the mandibular salivary gland of a cat

A cat was referred for investigation of a soft tissue mass caudal to the left mandible. Initial investigations suggested a malignant salivary gland tumour, and the mass was removed by extracapsular resection of the mandibular gland. Histopathology showed an oncocytoma within the salivary gland. An oncocytoma is a neoplastic transformation of oncocytes. Oncocytes are cells with a small nucleus and intense eosinophilic granular cytoplasm due to numerous mitochondria, which proliferate during ageing in exocrine and endocrine glandular tissues. Physiological proliferation occurs next to oncocytosis, oncocytoma, and oncocytic carcinoma. This is the first report of an oncocytoma in a feline mandibular salivary gland, and the first report of long-term survival after surgical removal.     

Cervical teratoma in a dog

A young adult boxer dog was examined for a painless swelling in the left cranial cervical area that was refractory to antibiotic therapy. Ultrasound examination revealed a hypoechoic mass abutting the rostrolateral aspect of the left mandibular salivary gland. The cystic mass was excised and was found to extend through the capsule of the salivary gland and appeared to be confluent with the glandular tissue at this point. Histopathological examination of the excised tissue demonstrated tissue from all 3 germinal layers. There was no indication of malignancy and the mass was diagnosed as a benign cervical teratoma. Hypotheses regarding the origin of teratomas in general are discussed and the origin of the teratoma in this case is suggested.     

Experimental rabies in skunks: mechanisms of infection of the salivary glands.

Striped skunks (Mephitis mephitis) were inoculated into the right submandibular salivary gland with street rabies virus. They were killed at various times after inoculation and several tissues were examined by immunofluorescence and light microscopy. Right and left superior cervical, nodose and trigeminal ganglia, medulla oblongata and at least three regions of right and left submandibular salivary glands were examined by the fluorescent antibody technique. Intracerebral titrations of salivary gland suspensions were made in weanling white Swiss mice. Immunofluorescent material (inoculum) was detected in septa and connective tissue surrounding secretory units of the right submandibular gland immediately after inoculation, but otherwise antigen was not detected in either right or left submandibular glands without coincident antigen in the medulla oblongata. This occurred first on day 12 in areas of the gland remote from the inoculation site. Titers of virus were low at this time. Serum neutralizing antibodies occurred by day 7 in a few skunks. The time of development and distribution of antigen strongly suggest that, even after direct inoculation, neural networks are necessary for development of widespread infection of the salivary gland. The early occurrence of serum neutralizing antibodies in some of the skunks suggests that the immune response was activated by virus in the inoculum since immunofluorescence was not detected in any tissue at this time.     

Technique of mandibular salivary gland biopsy in river otters (Lutra canadensis).

A Franklin-Silverman biopsy needle was used to obtain 2-5- x 1-2-mm mandibular salivary gland tissue samples percutaneously from nine North American river otters (Lutra canadensis). The samples were suitable for fluorescent antibody or polymerase chain reaction rabies testing. Ninety-two percent (11/12) of the biopsy procedures yielded histologically confirmed salivary gland tissue, and the remaining biopsy yielded adipose tissue. No complications were noted after 5-21 days.     

Spontaneous necrotizing sialometaplasia of the submandibular salivary gland in a Beagle dog

A single mass was found on the left submandibular salivary gland at necropsy of a 15-month-old male commercially bred laboratory Beagle dog from a control dose group from a repeat toxicity study. Microscopically, the mass was composed of a well-demarcated area of coagulative necrosis surrounded and separated from the normal salivary gland tissue by a thick fibrovascular capsule. Necrosis was admixed with areas of hemorrhage, fibrin, edema, fibrinoid necrosis of the vascular tunica media, and thrombosis of small and large vessels. Within the necrotic tissue, there was marked ductal hyperplasia, and squamous metaplasia of duct and acinar epithelium. The mass was diagnosed as necrotizing sialometaplasia of the submandibular gland. Hyperplastic ductal elements and squamous metaplasia can be mistaken microscopically with squamous cell carcinoma. Therefore, pathologists should be aware of this lesion as to avoid errors in the diagnosis of this benign pathologic condition.     

Carcinoma ex pleomorphic adenoma with sebaceous differentiation in the mandibular salivary gland of a dog

A carcinoma ex pleomorphic adenoma was diagnosed in the left mandibular salivary gland of an 8-year-old female spayed dog. The animal presented with a large nonpainful swelling in the left submandibular region. A computed tomography scan detected an irregularly enhancing soft tissue mass that was closely associated with the left external ear canal and extended to the left wing of the atlas. On surgical exploration, the mass was intimately associated with the left mandibular salivary gland. Both the mass and the adjacent gland were removed, and the diagnosis was determined by histopathology. The tumor was comprised of basaloid and low columnar epithelial cells, many glandular units formed by well-differentiated sebocytes, and multifocal regions of necrosis, mineralization, and hemorrhage. Salivary gland tumors with sebaceous differentiation are very rare in animals, with one previously reported case in a cat.     

Comparison of androst-16-ene steroid levels determined by a colorimetric assay with boar taint estimated by a trained sensory panel

A group of 17 intact male pigs and 3 gilts ranging in weight from 96 to 260 kg was selected for sensory evaluation of boar taint in loin chops. Samples were evaluated by 10 trained judges using a 10-cm graphic scale for rating off-aroma, off-flavor, pork flavor, softness, tenderness, juiciness, and residual tissue. In addition, a fry test for taint was conducted by four experienced testers on fat samples from all animals. Androst-16-ene steroid levels were measured in salivary gland and fat. Two versions of a colorimetric assay for the androst-16-ene steroids were used, a complete version, in which cholesterol was removed from the tissue extracts using a digitonin-Sepharose affinity column, and a simplified version, which does not include this step. The off-aroma and off-flavor sensory scores showed a good correlation with the androst-16-ene levels in fat and salivary glands and high correlations were obtained between the androst-16-ene steroid levels in fat and salivary glands. The levels of the androst-16-ene steroids in the salivary gland were highly correlated with the levels of estrogen in the blood and to a lesser extent with the levels of testosterone in the blood. Similar correlation coefficients were obtained between salivary gland androst-16-ene steroid levels measured using either the complete or simplified versions of the colorimetric assay and the off-aroma and off-flavor sensory scores. The results of the fry test were variable and no statistically significant correlations were obtained between the fry test results and the off-aroma and off-flavor sensory scores from the trained sensory panel.(ABSTRACT TRUNCATED AT 250 WORDS)     

Zygomatic salivary cyst with mucocele formation in a cat

An eight-year-old neutered male domestic shorthalr cat had a zygomatlc salivary cyst with associated mucocele formation. A fluctuating swelling developed ventral to the right eye, causing bulging of the lower eyelid, and a corresponding swelling was present in the caudal vestibule of the oral cavity. Cytological examination of the fluid obtained from asplratlon of the swelling was consistent with the appearance of saliva. A tentative dlagnosls of zygomatlc salivary mucocele was made. Surgical exploration and resectlon of the swelling demonstrated the presence of a multliobular cystic zygomatlc salivary gland. The histopathological appearance of the resected tissue was Interpreted as an Inflammatory reaction to mucus derived from a muitllocular salivary cyst.     

Parotid salivary duct sialocele associated with glandular duct stenosis in a cat

Feline parotid salivary duct sialocele is an uncommon disorder that has been previously reported in association with traumatic rupture of the duct in only two cats. Both cases were successfully treated by proximal duct ligation. We describe the successful surgical treatment of a parotid duct sialocele, secondary to spontaneous salivary duct stenosis, in an adult domestic shorthair cat. The cat was referred for assessment of a recurrent fluid-filled swelling on the left side of the face. Cytology of the aspirated fluid was consistent with serous saliva. The anatomical localisation of the lesion and the nature of the fluid were indicative of parotid gland/duct involvement. Retrograde sialography by parotid duct cannulation was unsuccessful because the left parotid duct opening was stenosed and obstructed by scar tissue. Surgical exploration revealed a parotid salivary duct sialocele, which was completely removed along with the parotid gland without complications.     

Concurrent sialocoele and necrotising sialadenitis in a dog

A seven-year-old male, entire rottweiler was presented to Murdoch University Veterinary Hospital with a 24 hour history of blindness, chemosis, exophthalmus, pain on opening the mouth and hypersialism. Bilateral mandibular and zygomatic salivary gland enlargement with concurrent bilateral zygomatic salivary gland sialocoeles were identified. The cause of the mandibular salivary gland enlargement was confirmed as necrotising sialadenitis, while the cause of the zygomatic gland enlargement was presumed to be because of a similar disease process. No underlying aetiology was identified. Treatment consisted of supportive management, corticosteroids and paracentesis of the sialocoeles and resulted in resolution of the salivary gland enlargement and the associated clinical signs. This is an unusual presentation of salivary gland disease in the dog with multiple gland involvement and a spectrum of disease processes occurring at the same time.     

Zygomatic sialocele secondary to infarction treated with sialoadenectomy in a dog

Zygomatic salivary gland disease is not commonly reported in dogs and there is a paucity of literature reporting salivary gland disease secondary to infarction in dogs. A 9-year-old German wirehaired pointer presented with left eye exophthalmos, 3rd eyelid elevation, negative retropulsion, and pain upon opening of the mouth. Computed tomography revealed a mass extending from the left zygomatic salivary gland, consistent with a sialocele. A left-sided zygomatic sialoadenectomy was performed successfully. Histopathologic diagnosis concluded zygomatic salivary gland infarction. The dog had no signs of recurrence 20 mo after surgery.Key clinical message:To the authors’ knowledge, this is the first case report with long-term outcome of a zygomatic sialocele secondary to salivary gland infarction in a dog treated by zygomatic sialoadenectomy via zygomatic osteotomy.     

Salivary Gland Adenocarcinoma in a Domestic Rabbit (Oryctolagus cuniculus)

A 2.4 kg, 7-year-old, female Rex rabbit was presented with a 4-month history of a left-sided head tilt, difficulty in mastication, lethargy, and chronic wasting. Diagnostic testing of the patient revealed a severe heterophilic leukocytosis and radiographic images of the skull radiographs indicated irregularity of the left tympanic bulla. A computed tomographic scan highlighted a heterogeneously contrast-enhancing mass, ventral and rostral to the left tympanic bulla, with contrast enhancement of the meninges on the left, consistent with an aggressive neoplasm. The patient was euthanized and the mass was identified as a salivary gland adenocarcinoma. The gland of origin is suspected to be the left parotid, owing to its location and close association with normal parotid tissue. To the authors' knowledge, this is the first report of a salivary gland adenocarcinoma in a domestic rabbit. A computed tomography (CT) scan and histopathology examination were useful modalities for identifying the neoplasm in this case.     

成年皖西白鹅母鹅消化腺的形态学观察

本试验研究了成年皖西白鹅母鹅消化腺的形态特征。实验应用20只皖西白鹅母鹅。鹅放血致死后,解剖观察消化腺的组成,取消化腺的各部分,制作组织切片。结果表明:成年皖西白鹅母鹅消化腺由唾液腺、肝脏和胰腺组成。肝脏的组织结构由肝小叶和门管区构成,肝小叶由中央静脉、肝细胞管和肝窦组成,门管区包括小叶间胆管、小叶间动脉和小叶间静脉,还有淋巴组织分布。胰腺包括外分泌部和内分泌部,外分泌部由腺泡和导管组成,内分泌部为一细胞团,即胰岛。     

First case of salivary mucocele originating from the minor salivary gland of the soft palate in a dog

We found a case of salivary mucocele that originated in the minor salivary gland (palatine gland) of the soft palate in a dog. At first admission, the soft palate swelled remarkably. Computed tomography (CT) revealed cystic radiolucency inside a large quantity of liquid in the soft palate, and most of the airway was occupied. Marsupialization was performed, but since a recurrence was observed one month later, the salivary mucocele was removed. There has been no report of salivary mucocele arising from the minor salivary gland of the soft palate in dogs. To our knowledge, this case is the first. Complete removal, including minor salivary glands surrounding the lesion, is necessary for treatment of salivary mucocele in dogs.     

Detection of Neorickettsia (Ehrlichia) risticii in tissues of mice experimentally infected with cercariae of trematodes by in situ hybridization

Neorickettsia (Ehrlichia) risticii was demonstrated to occur in cercariae developing in Juga yrekaensis snails by experimental transmission, genetic detection and histopathology. Cercariae were isolated from the digestive glands of snails collected in a fresh stream water area of Siskiyou County, CA, and inoculated into CF1 mice. Mice developed clinical signs, splenomegaly and histopathologic abnormalities. The agent was maintained by serial passages of whole blood in CF1 mice. A 527-bp product of the 16S rRNA gene of N. risticii was serially detected by nested PCR in blood, feces, salivary gland, suprarenal gland, spleen, intestine and bone marrow of inoculated mice. N. risticii DNA was detected by in situ hybridization with DIG-labeled probe in PCR-positive salivary gland, intestine and spleen tissue sections of experimental mice on day 30 after inoculation. Infection in mice was established when cercariae were inoculated by either IP or SC routes but not established following intraoral route. N. risticii was detected by PCR in spleen, intestine and bone marrow even after 73 days post-inoculation whereas blood from the same animals became negative at 58 days. N. risticii was observed by in situ hybridization in salivary gland, spleen and intestine of mice infected by IP or SC inoculation. This ISH protocol should aid investigations on the host range of the Neorickettsiosis and pathogenesis of neorickettiosis in vector, animal or human.     

Idiopathic salivary gland enlargement (sialadenosis) in dogs: a microscopic study

A histological, histochemical and morphometric study was performed on submandibular salivary glands from 13 dogs which had presented with a submandibular mass or swelling that proved to be a portion of non-inflammatory and non-neoplastic submandibular salivary gland. There were no consistent changes in lectin-binding histochemistry or immunohistochemical expression of various cell markers, and, in most cases, there was no measurable difference in acinar size in the affected gland. The possible explanation for the clinical salivary gland enlargement is therefore unclear.     

Keratoconjunctivitis sicca: immunological evaluation of 62 canine cases

The etiology of keratoconjunctivitis sicca (KCS) in 62 dogs was evaluated, using immunologic techniques. Using direct fluorescent antibody testing, autoantibodies within the lacrimal, salivary, or pancreatic glands were detected in 5 of 8 dogs tested. Circulating antibodies to the nictitating membrane gland, main lacrimal gland, parotid salivary gland, or mandibular salivary gland were detected using indirect fluorescent antibodies in 9 of 31, 3 of 31, 5 of 31, and 5 of 31 sera, respectively. Using radial immunodiffusion, hyper-gamma-globulinemia was detected in 21 of 30 dogs with KCS. Antinuclear antibodies, primarily in a nucleolar pattern, were demonstrated in 20 of 50 dogs with KCS. Lymphocytic infiltrates were evident in 5 of 9 labial salivary biopsies, 2 of 4 parotid gland specimens, 2 of 4 mandibular gland specimens, and 2 of 3 thyroid gland specimens taken from dogs with KCS. Autoimmune diseases had been previously documented in 4 of 62 dogs. Twenty-five of the 62 dogs (40%) had concurrent problems indicative of an underlying immunologic disorder.