Idiopathic phenobarbital‐responsive hypersialosis in the dog: an unusual form of limbic epilepsy?

Three unusual cases of salivary gland enlargement and hypersialosis in the dog that responded to anticonvulsant therapy are reported. Presenting complaints included weight loss, hypersalivation, retching and vomiting of several weeks' duration. Two dogs were presented with enlarged painful mandibular salivary glands. The third dog exhibited bizarre behaviour (including jaw chattering) and developed enlarged painful mandibular salivary glands during hospitalisation. Fine needle aspirate cytology and biopsies from the enlarged salivary glands revealed no significant pathological changes. In one dog, an electroencephalogram revealed changes consistent with epilepsy. Hypersialism and salivary gland enlargement resolved completely during phenobarbital administration in all cases. Two dogs were successfully weaned off treatment six months after diagnosis. The remaining dog relapsed after eight months, but normalised with the addition of oral potassium bromide. It is hypothesised that the syndrome idiopathic hypersialosis may in fact be an unusual form of limbic epilepsy.     

Presumptive sialadenosis in a cat

A cat was presented with signs associated with enlargement of the mandibular salivary glands. Histological findings were normal, consistent with a diagnosis of sialadenosis, and the cat responded to symptomatic treatment with oral phenobarbitone.     

CT sialography in the dog - a cadaver study

To document computed tomographic topography of salivary glands and their ducts in dogs, a retrograde filling with methylcellulose and iodinated contrast medium was performed in three cadavers. Demarcation of the parotid, mandibular and zygomatic glands was achieved. Surrounding structures were imaged without beam hardening artefacts. Landmarks for the parotid, mandibular and zygomatic glands were the external acoustic canal, the mandibular angle and the pterygopalatine fossa, respectively. Sialograms of the parotid, mandibular and zygomatic ducts were achieved, whereas neither the sublingual glands nor their ducts could be contrasted. The images provide a three-dimensional visualization of the salivary glands and their ducts.     

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.     

Sialography of sheep parotid and mandibular salivary glands

The anatomy of ovine salivary glands was studied on cadaver heads. The mandibular duct enters the oral cavity on the ventral surface of sublingual caruncles, which are located medial to the orifice of the ventral sublingual gland duct. The parotid gland duct enters the oral cavity on the cheek opposite the upper 2nd molar. Prior to applying sialography to live animals, the procedure was carried out on cadaver heads then the live animals were sedated, the mandibular and parotid ducts catheterized and contrast medium was injected into each gland. Lateral radiographs were made immediately after the injection. The normal sheep mandibular and parotid salivary glands have a multilobular appearance in cadaver heads, but in live animal only the ducts and their smaller branches could be identified. The mean diameter of mandibular and parotid duct were 1.4+/-0.3 mm and 3. 1+/-1.0 mm respectively. The monostomatic sublingular gland had a slender shape in the sialogram. In conclusion sialography of mandibular, parotid and sublingual salivary glands in sheep is practical and can be helpful in diagnosis of pathological conditions of these glands.     

MR anatomy of salivary glands in the dog

This retrospective analysis documented the magnetic resonance imaging (MRI) appearance of normal salivary glands based on 101 studies in dogs with no detectable disease in the splanchnocranium. Surface, signal intensity, homogeneity, structure, symmetry and the relationship of glands to surrounding tissues were noted, and gland topography was assessed with E12 plastinated embedded sections. Signal intensity of salivary glands was isointense (7-40%) to hyperintense (60-90%) to muscle tissue on T1- and hyperintense on T2-weighted images. Salivary glands had an increased T1 signal after contrast medium was applied. Salivary gland structure appeared homogeneous in mandibular and major sublingual glands and heterogeneous in zygomatic and parotid glands. Consistent landmarks were the external auditory canal for parotid glands, the digastric muscle for mandibular and major sublingual glands, and the pterygopalatine fossa for zygomatic glands. The minor sublingual and ventral buccal glands could not be localized with low-field MRI.     

Histological Structure and Distribution of Carbonic Anhydrase Isozymes (CA‐I,II, III and VI) in Major Salivary Glands in Koalas

While the mandibular glands usually consist of only mucous acinar cells or a combination of mucous and serous cells in other species of mammals, those of koalas were serous glands. Rabbit mono‐specific polyclonal anti‐canine CA‐I, II, III or VI antiserum showed cross‐reactivity against corresponding koala carbonic anhydrase (CA) isozymes. Although immunohistochemical reactions to CA‐I, II and VI in ductal cells were moderate to strong in the tested salivary glands, no reaction or only slight reactions were observed against CA‐III. In the sublingual glands, moderate immunohistochemical reactions to CA‐I, II and VI were also evident in serous acinar cells and serous demilunes. However, no reactions to the tested isozymes were observed in mucous acinar cells in these glands. With the exception of the histological structure of the mandibular glands, histological features and the distributional profile of CA isozymes of the salivary glands in koalas are relatively close to results obtained from horses.     

Necrotising sialoadenitis in a wire-haired fox terrier

Bilateral mandibular salivary gland infarction was diagnosed in a young mature wire-haired fox terrier with a protracted history of drooling, loss of appetite, retching and vomiting. The signs were not alleviated following surgical removal of the glands. Despite supportive therapy, the animal's condition did not improve and it was killed. Histologically the enlarged affected salivary glands were almost entirely necrotic and there was evidence of reactive inflammation peripherally. The necrosis was interpreted as being due to ischaemia. The only other significant pathological findings were compensatory hypertrophy and hyperplasia of the parotid salivary glands.     

Salivary gland necrosis in a wire-haired fox terrier

A 2%year-old wire-haired fox terrier had a 2-month history of inappetance, gagging, retching, regurgitation and vomiting associated with bilateral necrosis of the mandibular salivary glands. Surgical removal of the glands did not greatly improve the demeanor of the dog, or alleviate the regurgitation and vomiting. Euthanasia was recommended because of the failure to respond to supportive therapy. The affected glands were enlarged and showed infarction with peripheral reactive inflammation. Compensatory hypertrophy and hyperplasia of the parotid salivary glands were the only other significant pathological findings. No explanation for the vomiting could be found.     

Cytoarchitectural differences of myoepithelial cells among goat major salivary glands

Previously, the distribution of myoepithelial cells (mecs) in the salivary glands was studied by both immunohistochemistry, and transmission electron microscopy; however, little was elucidated concerning their morphological features, especially in goats. This study was performed to investigate the correlation between the cytoarchitecture of the mecs in goat major salivary glands (parotid, mandibular, and sublingual glands) and the nature of the saliva secretion. The cytoarchitectural features of the mecs were examined by scanning and transmission electron microscopy as well as immunohistochemically. The secretory endpieces in the parotid gland are of the pure serous type, but in both the mandibular and sublingual glands they are of the mixed type. In all studied glands, the intercalated ducts were covered by mecs which, unlike the large stellate cells that surrounded the secretory endpieces, were spindle-shaped with few cytoplasmic processes. Interestingly, the mecs were found to bulge on the basal surfaces of the serous acini and intercalated ducts in all glands and to be in close contact to the seromucous tubules surface in the mandibular and sublingual glands forming a continuous network around it. In conclusion, the differences in the degree of development of the mecs as well as the number of their cytoplasmic processes may be correlated with the nature of the secretion and the number of the secretory granules. Thus these observations may have some relevance in the diagnosis of atrophy and pathogenic conditions of these glands.     

Lectin Histochemistry of Glycoconjugates in Horse Salivary Glands

The glycoconjugate content of major horse salivary glands was investigated by means of horseradish peroxidase-conjugated lectins. Qualitative differences were observed in the terminal sugar residues of secretory glycoproteins and glycoconjugates linked to the apical surface of excretory duct epithelial cells. Mucous acinar cells in mandibular and sublingual glands contained oligosaccharides with D-galactose, α- and β-N-acetylgalactosamine, N-acetylglucosamine and fucose residues, whereas mandibular, sublingual and parotid serous cells contained only oligosaccharides with terminal α- and β-N-acetylgalactosamine residues. The apical portion of striated and interlobular duct lining cells of mandibular and sublingual glands stained for α- and β-N-acetylgalactosamine and for N-acetylglucosamine. In parotid gland the cytoplasm of intercalated duct cells and the apical surface of striated duct epithelial cells stained for α-N-acetylgalactosamine.     

A pathological study of the salivary glands of rabid dogs in the Philippines

Rabies is a zoonotic disease caused by the rabies virus. While the salivary glands are important as exit and propagation sites for the rabies virus, the mechanisms of rabies excretion remain unclear. Here, we investigated the histopathology of the salivary glands of rabid dogs and analyzed the mechanism of excretion into the oral cavity. Mandibular and parotid glands of 22 rabid dogs and three control dogs were used. Mild to moderate non-suppurative sialadenitis was observed in the mandibular glands of 19 of the 22 dogs, characterized by loss of acinar epithelium and infiltration by lymphoplasmacytic cells. Viral antigens were detected in the mucous acinar epithelium, ganglion neurons and myoepithelium. Acinar epithelium and lymphocytes were positive for anti-caspase-3 antibodies and TUNEL staining. In contrast, no notable findings were observed in the ductal epithelial cells and serous demilune. In the parotid gland, the acinar cells, myoepithelium and ductal epithelium all tested negative. These findings confirmed the path through which the rabies virus descends along the facial nerve after proliferation in the brain to reach the ganglion neurons of the mandibular gland, subsequently traveling to the acinar epithelium via the salivary gland myoepithelium. Furthermore, the observation that nerve endings passing through the myoepithelium were absent from the ductal system suggested that viral proliferation and cytotoxicity could not occur there, ensuring that secretions containing the virus are efficiently excreted into the oral cavity.     

Sublingual salivary gland sialolithiasis in a dog

A case of sialolithiasis of the sublingual/mandibular salivary gland and duct complex in a dog was reported. Sialoadenectomy of the ipsilateral glands successfully treated the associated sialocele.     

Intestinal choristoma in the midcervical region of a dog

A 5-year-old, neutered male, mixed-breed dog was evaluated for a fluctuant mass in the right midcervical region. The mass recurred following aspiration of its contents and after removal of the right sublingual and mandibular salivary glands. The lateral midcervical location of the mass and the serous nature of the fluid within the mass were inconsistent with a salivary mucocele. Excisional biopsy was curative and revealed an intestinal choristoma.     

Histology, carbohydrate and protein histochemistry of the mandibular gland in suckling, prepuberal and puberal zebus (Bos indicus)

Histological, histometric and histochemical studies of the mandibular salivary glands of suckling, prepuberal and puberal zebu were carried out using 14 male animals. The developmental growth of this gland is characterized and correlated with histochemical development. These findings were correlated with other similar studies of Bovidae.     

MULTIMODALITY IMAGE FUSION TO FACILITATE ANATOMIC LOCALIZATION OF 99MTC-PERTECHNETATE UPTAKE IN THE FELINE HEAD

99mTc-pertechnetate is excreted in humans by the thyroid glands, gastric mucosa, salivary glands, choroid plexus, and sweat glands. Uptake attributed to the zygomatic and molar salivary glands is used commonly as a reference to assess thyroid uptake and differentiate euthyroid from hyperthyroid cats. However, the exact location and origin of uptake of 99mTc-pertechnetate in the head during thyroid scintigraphy in cats remains uncertain. The purpose of this study was to localize uptake of 99mTc-pertechnetate in the head of the cat using multimodality image fusion. Computed tomography (CT), magnetic resonance (MR), and single photon emission tomography (SPECT) imaging were performed successively in two cats during the same anesthesia procedure. Transverse, dorsal, and sagittal images were reconstructed for each modality. Images were rescaled and fused manually. The anatomic location of focal 99mTc activity in SPECT images was identified in CT and MR images. Four major and four minor focal areas of uptakes were identified in the head in both cats. A rostral conical-shaped activity was identified in the nasal cavity. Two symmetric focal areas of uptakes seen in the soft tissues in the ventro-caudal retro-bulbar region, and rostro-medial to the vertical ramus of the mandible were attributed to zygomatic salivary glands. A central focal activity located ventral and caudal to the zygomatic uptake was located in the nasopharynx and soft palate. Minor symmetric areas of uptake identified in the retromandibular region were attributed to parotid and mandibular salivary glands. Minor symmetric areas of uptake identified in the region of the mandible were attributed to molar salivary glands. No focal area of uptake was identified in the brain.     

Metaplastic ossification of a cervical sialocoele in a dog

Metaplastic ossification of a long-standing cervical sialocoele was identified in a 2-year-old male Hellenic Hound dog. Diagnosis was based upon history, clinical findings, paracentesis and histopathology. Trauma or chronic inflammation of the mandibular gland/duct complex were the most probable causes of the ossification. Surgical excision of the ossified mass, as well as of mandibular and sublingual salivary glands/ducts of the affected side, resulted in clinical remission.     

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.     

SIALOGRAPHY IN CATTLE: TECHNIQUE AND NORMAL APPEARANCE

Sialography of the bovine mandibular and parotid salivary glands was performed by injecting iodinated, water soluble contrast medium into the respective ducts. The anatomy of the above mentioned salivary glands was studied on cadaver heads. The mandibular duct enters the oral cavity on the ventral surface of the sublingual caruncles, which are located medial to the orifice of the ventral sublingual gland duct. The parotid gland duct enters the oral cavity on the cheek opposite the upper 2nd molar (Sth cheek tooth). Prior to applying sialography to live animals, the technique of catheterization, injection and radiography had to be developed, which was carried out on cadaver heads. Subsequently the technique was applied to 5 live animals. The animals were sedated, the mandibular and parotid ducts catheterized, and contrast medium was injected into each gland. Latero-lateral radiographs were made immediately after the injection. The normal bovine mandibular and parotid glands, as depicted on sialograms, have a multilobutated appearance in cadaver heads, but in the live animal only the ducts and their smaller branches could be identified. The parotid duct leaves the deep surface of the rostral end of the gland and courses along the border of the masseter muscle before it enters the mouth. The mean diameter of the duct was 4.2 ± 0.3 mm. The mandibular duct is composed of a rostral and a caudal branch. The caudal branch describes a semi circular turn prior to joining the rostral branch. The mean diameter of the main duct was 2.8 ± 0.4 mm.     

Abnormal changes in both mandibular salivary glands in a dog: Non-mineral radiopaque sialoliths

A 10-year-old Maltese dog was presented with a firm mass on the left side of his neck. Physical examination confirmed a firm mass in the left and a submandibular swelling in the right cervical region. Sialolithiasis and associated sialocele in both mandibular salivary glands were suspected and bilateral sialoadenectomy was performed. The stones were identified as non-mineral sialoliths.