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.     

Adenocarcinoma of the salivary gland in a white Swiss mouse.

A salivary gland adenocarcinoma in a white Swiss mouse used in a titration of the scrapie agent is reported. The neoplasm originated from the serous cells of the parotid salivary gland. Retroviral particles were detected in the neoplastic salivary gland cells by electron microscopy.     

Pathological features of salivary gland cysts in a Shiba dog with GM1 gangliosidosis: a possible misdiagnosis as malignancy

Salivary gland cysts are often concurrent with GM1 gangliosidosis in Shiba dogs. Although the etiology is unknown, these cysts may be misdiagnosed as malignant due to the accumulation of foamy cells. The present study investigated the cytological, histopathological, immunohistochemical and electron microscopic characteristics of salivary gland cysts in a Shiba dog affected with GM1 gangliosidosis. The salivary gland masses were surgically enucleated and examined clinicopathologically and pathologically in a 7-month-old Shiba dog with GM1 gangliosidosis. Many large cells with rich cytoplasm including vacuoles of various sizes, i.e., foamy cells, were observed in stamp smears from the cut-surface of the masses and histopathologically in major parts of the cyst wall. Some of these foamy cells presented features similar to a spider-web appearance. The foamy cells were confirmed to have originated from macrophages based on marked immunohistochemical expression of vimentin, HLA-DR, lysozyme and Iba1. An ultrastructural study demonstrated electron-dense vesicular structures in the vacuolated cells. Therefore, the masses were diagnosed pathologically as benign salivary gland cysts with accumulation of foamy cells. In conclusion, the histopathological features of the salivary gland cysts in this Shiba dog were similar to those of lipoma and/or liposarcoma. In such cases, immunohistochemical and ultrastructural examinations were useful in the differential diagnosis. Practitioners, clinical pathologists and pathologists should take GM1 gangliosidosis into consideration when they encounter salivary gland cysts in Shiba dogs.     

Preliminary studies of the development of Anaplasma marginale in salivary glands of adult, feeding Dermacentor andersoni ticks

On each day of feeding on susceptible calves, salivary glands obtained from groups of adult ticks that transmitted Anaplasma marginale were examined for A marginale colonies by use of light microscopy and transmission electron microscopy. On day 8 of feeding, salivary glands were examined, using fluorescein-labeled antibody and methyl green-pyronine stain. Use of fluorescein-labeled antibody consistently revealed small numbers of fluorescent foci in salivary gland acinar cells obtained from ticks that had fed for 8 days. Colonies of A marginale were seen by transmission electron microscopy only in salivary gland acini of male ticks; these colonies could not be identified, using light microscopy, in companion 1-micron plastic sections stained with Mallory stain. Methyl green-pyronine stain, used commonly to detect theilerial parasites in tick salivary glands, did not differentiate A marginale from cytoplasmic inclusions normally found in salivary gland acinar cells.     

Mast cell tumor in the mandibular salivary gland in a dog

A mast cell tumor in the mandibular salivary gland was diagnosed in a 9-year-old English Setter. Dense infiltrating sheets of mast cells were present within the mandibular salivary gland, the medial retropharyngeal lymph node and in two subcutaneous masses on the flank. The salivary gland, lymph node, and masses were excised. The dog was treated postoperatively with the histamine receptor antagonist, cimetidine and the alkylating agent, chlorambucil. The tumor recurred at the angle of the mandible 4 months later and the dog was killed.     

Adenocarcinoma of the parotid salivary gland in a cow

A 6‐year‐old Girolando dairy cow was presented for evaluation of a large subcutaneous facial mass. Fine‐needle aspirates of the mass contained many neoplastic cells with high nuclear:cytoplasmic ratios arranged in sheets and loosely cohesive clusters with streaming erythrocytes and neutrophils in the background. Neoplastic cells were 13–25 μm in diameter and were round to cuboidal with variably distinct borders. Based on the signalment, anatomic location, and cytologic findings, differential diagnoses included salivary adenocarcinoma, squamous cell carcinoma, and mucoepidermoid carcinoma. The cow was euthanized and a necropsy was performed. The primary neoplasm arose from the left parotid salivary gland and meastatic tumor was found in the regional lymph nodes and lung. Histologically, the tumor was composed of anastomosing and irregular solid islets surrounded by scant stroma. Cells were negative for periodic acid‐Schiff (PAS), PAS‐diastase, and Alcian blue pH 2.5 stains, used to detect mucin. On immunohistochemical analysis, neoplastic luminal salivary gland cells expressed cytokeratin, but not S100, α‐smooth muscle actin, or vimentin. Peripheral cells of neoplastic islets were immunoreactive for p63. The final diagnosis was nonsecretory adenocarcinoma of the parotid salivary gland.     

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.     

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.     

Characterisation of sugar residues in glycoconjugates of pig mandibular gland by traditional and lectin histochemistry

Sugar residues are important components of salivary gland secretion. Traditional histochemical methods and lectin histochemistry were used to characterise glycoconjugates present in the mandibular gland of normal adult pigs. Acinar cells contained abundant quantities of glycoconjugates with the terminal trisaccharide sialic acid - (alpha 2-->3, 6) galactosyl (beta 1-->3) N -acetylgalactosamine. Mandibular acinar cells also contained alpha and beta N -acetylgalactosamine and N -acetylglucosamine residues, whereas the demilunar cells contained glycoconjugates with fucose, mannose and N -acetylglucosamine residues. In the duct system a range of sugar residues were localised throughout the cell cytoplasm or limited to the apical surface. These results provide new knowledge concerning the structure of salivary glycoconjugates in normal adult pig and a basis for future pathological studies.     

Histological and histochemical studies on the lingual, preglottal and laryngeal salivary glands of the Japanese quail (Coturnix coturnix japonica) at the post-hatching period

The postnatal development and histochemistry of mucins of the lingual, preglottal and laryngeal glands in the quails were investigated by means of light microscopy using specific staining for complex carbohydrates. In this study, the tongues were taken from female and male quails from day 1 to day 60 after hatching. The salivary glands in quail's tongue comprised the lingual gland, with lateral and medial (paraentoglossal gland) portions that differ in morphology and histochemical staining, and the preglottal gland, with two lateral portions and one medial portion. The medial portion of the preglottal gland, which extended to the row of the laryngeal papillae on each side of the glottis, was described as the laryngeal gland. The salivary glands were present at hatching and their cells were functionally mature and secreted mucins. In quail of all ages, the histochemical reactions revealed that the cytoplasms of the secretory cells of the preglottal, laryngeal and paraentoglossal gland (medial portion of lingual gland) contained sialomucins and weakly sulphated epithelial mucins. Neutral mucins were absent in the paraentoglossal gland, while a small amount of neutral mucins was present in other glands. The mucins with vicinal diol groups, sialomucins and weakly sulphated epithelial mucins were mixed within the secretory cells of all the glands. All the histochemical reactions were restricted to the supranuclear regions of the secretory cells within the lateral portion of the lingual gland. In conclusion, the contents of mucins in the lingual, preglottal and laryngeal glands varied between different age groups, however, no differences in the glands' histochemistry between male and female quails were observed.     

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.     

Morphology and development of Cowdria ruminantium in Amblyomma ticks

The morphology and development of Cowdria ruminantium have been studied in Amblyomma hebraeum and A. variegatum. Colonies of C. ruminantium have so far been demonstrated microscopically in gut, salivary gland cells, haemocytes and malphighian tubules of infected Amblyomma ticks. Colonies in gut cells were seen in both unfed and feeding ticks but colonies in salivary gland acini were observed only in nymphs that had fed for 4 days. Although the predominant type seen in both tick stages was the reticulated form that appeared to divide by binary fission, electron dense forms were also present. The latter are similar to those forms documented in endothelial cells of the vertebrate host as well as in cell culture. The presence of colonies of C. ruminantium in salivary glands of feeding ticks, along with the demonstration of different morphologic forms of the organism, suggests that a developmental cycle of the organism occurs in its invertebrate host. It is thought that organisms first infect and develop within gut cells. From there subsequent stages continue their development in haemolymph and salivary glands and are then transferred to the vertebrate host during tick feeding. Further studies are needed to completely understand the development of C. ruminantium in ticks and its subsequent transmission by these parasites.     

Extramedullary plasmacytoma of the salivary gland in two Syrian hamsters (Mesocricetus auratus)

Two Syrian hamsters developed marked swelling of the ventral neck. Histologic examination of both masses revealed that the submaxillary salivary glands were effaced by large numbers of neoplastic plasma cells. In one hamster, neoplastic cells had infiltrated the adjacent lymph node. The neoplastic cells expressed CD79a antigen and were negative for CD3, lambda, and kappa light chains. Ultrastructural features of neoplastic cells in the salivary gland of one hamster included abundant cytoplasmic rough endoplasmic reticulum profiles, and peripherally displaced nuclei that contained marginated heterochromatin, consistent with plasma cells. Salivary gland plasmacytomas are extremely rare in humans and have not previously been reported in nonhuman species. The occurrence of such neoplasms in two hamsters suggests that this species may be predisposed to developing tumors of this type.     

Malignant fibrous histiocytoma (giant cell type) associated with a malignant mixed tumor in the salivary gland of a dog

A 12-year-old male Boxer dog presented with a 5 x 5 x 7-cm partially encapsulated mass in the right mandibular salivary gland. Histologically, the mass was composed of neoplastic epithelial and mesenchymal cells. The mesenchymal component consisted of two cell populations arranged in different patterns: coalescing nodules of neoplastic mononuclear cells with rare osteoid and numerous osteoclastlike giant cells; and sheets of neoplastic spindle cells intermingled with neoplastic epithelial cells and containing osteoid and well-formed bone trabeculae lined by osteoblasts and few osteoclastlike giant cells. On the basis of these histological features, two malignant salivary tumors were diagnosed: a malignant fibrous histiocytoma (giant cell type) and a malignant mixed tumor. Immunohistochemical studies demonstrated keratin 5 and 8 expression by the neoplastic epithelial cells, indicating a probable salivary ductal origin, and vimentin expression by all mesenchymal elements, suggesting a fibroblastic line of differentiation.     

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.     

Ultrastructural features of Cowdria ruminantium in midgut epithelial cells and salivary glands of nymphal Amblyomma hebraeum

Colonies of Cowdria ruminantium were studied in midgut epithelial cells and salivary gland acini of nymphal Amblyomma hebraeum that were infected experimentally as larvae. Colonies were found in both tissues and studied with light and electron microscopy. Colonies observed within gut cells frequently contained 2 types of the organism: electron-dense and reticulated forms. The morphology of colonies from salivary glands, as seen with light microscopy, varied from compact, densely-staining, small colonies to larger ones in which individual organisms were apparent. With electron microscopy, most organisms in salivary glands were reticulated and appeared to be dividing by binary fission. In both types of host cells, colonies often contained a dense inclusion to which reticulated organisms were adhered.     

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.     

Effect of four sedative and anesthetic protocols on quantitative thyroid scintigraphy in euthyroid cats

OBJECTIVES: To determine the effect of sedation and anesthesia on thyroid and salivary gland uptake of technetium Tc 99m pertechnetate ((99m)TcO(4)) in euthyroid cats. ANIMALS: 6 euthyroid cats. PROCEDURES: Thyroid scintigraphy was performed by use of a high-resolution low-energy parallel-hole collimator after IV injection of 117 to 133 MBq (3.16 to 3.59 mCi) of (99m)TcO(4)(-). The procedure was performed 4 times on each cat during different sedative and anesthetic protocols in a rotating schedule as follows: propofol, ketamine-midazolam-atropine, ketaminemidazolam, and medetomidine. Regions of interest were drawn around thyroid and salivary glands and counts corrected for background and decay. Percentage of (99m)TcO(4)(-) uptake in salivary and thyroid glands and thyroid-to-salivary gland (99m)TcO(4)(-) uptake ratio were calculated at 20 and 40 minutes. Relative effects of anesthesia and sedation on salivary and thyroid gland (99m)TcO(4)(-) uptake were compared. RESULTS: Significant differences among sedativeanesthetic protocols were found for thyroid gland (99m)TcO(4)(-) uptake, salivary gland (99m)TcO(4)(-) uptake, and thyroid-to-salivary gland (99m)TcO(4)(-) uptake ratio. Thyroid gland (99m)TcO(4)(-) uptake for the ketamine-midazolam protocol at 20 and 40 minutes after (99m)TcO(4)(-) administration was significantly higher than for the propofol protocol. A significant difference in salivary gland(99m) TcO(4)(-) uptake was found between ketamine-midazolam and ketamine-midazolam-atropine protocols at 40 minutes. The thyroid-to-salivary gland (99m)TcO(4)(-) uptake ratio for the ketamine-midazolam protocol was significantly higher at 40 minutes than for propofol or ketamine-midazolam-atropine protocols. CONCLUSIONS AND CLINICAL RELEVANCE: Sedation and anesthesia have a significant effect on thyroid and salivary gland (99m)TcO(4) uptake in euthyroid cats that may interfere with thyroid scintigraphic image interpretation.