RPCV (2015) 110 (595-596) 229-232

Basal cell adenoma of zygomatic salivary gland in a young dog – First case report in Mozambique

Adenoma das células basais da glândula salivar zigomática em cão jovem – Primeiro relato de caso em Moçambique

Ivan F. Charas dos Santos*1,2, José M.M. Cardoso1, Giovanna C. Brombini3 Bruna Brancalion3

1Departamento de Cirurgia, Faculdade de Veterinária, Universidade Eduardo Mondlane, Maputo, Moçambique 2Pós-doutorando (Bolsista FAPESP), Departamento de Cirurgia e Anestesiologia Veterinária, Faculdade de Medicina Veterinária e Zootecnia (FMVZ), Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brasil. 3Faculdade de Medicina Veterinária e Zootecnia (FMVZ), Universidade Estadual Paulista (UNESP),Botucatu, São Paulo, Brasil.

Summary: of zygomatic salivary gland Introduction was described in a 1.2 years old Rottweiler dog with swelling of right zygomatic region tissue. Clinical signs were related to Salivary glands diseases in small animals include anorexia, slight pain on either opening of the mouth. Complete blood count, serum biochemistry, urinalysis, thoracic radio- mucocele, , , sialad- graphic examination; and transabdominal ultrasound showed enosis, and less neoplasia (Spangler and no alteration. The findings of cytology examination were con- Culbertson, 1991; Johnson, 2008). Primary tumours sistent with benign tumour and surgical treatment was elected. of salivary glands are rare in dogs and not common- The histopathologic examinations were consistent with basal ly reported in small animals. The incidence is about cell adenoma of zygomatic salivary gland. Seven days after the surgery no alteration was observed. One year later, the dog re- 0.17% in dogs with age between 10 and 12 years turned to check up and confirmed that the dog was healthy and old (Spangler and Culbertson, 1991; Hammer et al., free of clinical and laboratorial signs of tumour recurrence or 2001; Head and Else, 2002). Overall incidence is 1.6 metastases. Reports of basal cell adenoma of salivary gland in benign tumours per 100,000 dogs at risk (Head and young dogs were lack on the veterinary literature. To author’s Else, 2002). knowledge, this was the first report of clinical and surgery de- scription of basal cell adenoma of zygomatic salivary gland in of salivary gland are more com- a young dog in Mozambique. mon than adenomas in dogs and cats, and represent 5% of all salivary gland tumours. Overall incidence Keywords: Dog, epithelial cells, salivary gland, tumour. is 3.1 per 100,000 dogs at risk (Spangler and Cul- bertson, 1991; Hammer et al., 2001; Head and Else, Resumo: Adenoma das células basais de glândula salivar zigo- mática foi descrito em cão da raça Rottweiler, macho, 1,2 anos 2002). No breeder or sex predilection is reported de idade, pesando 38 kg, com tumefação da região zigomática (Hammer et al., 2001; Head and Else, 2002) and pa- direita. Os sinais clínicos foram relacionados com anorexia e rotid and mandibular salivary glands are most affect- dor ligeira durante a abertura da boca. O hemograma, exame ed and represent 75 - 80%, respectively (Hammer et bioquímico sérico, urinálise, exame radiográfico de tórax, e al., 2001). Furthermore, the zygomatic salivary gland ultrassonografia transabdominal não demonstraram alteração. O exame citológico foi compatível com tumor benigno e o tra- is not frequently affected by tumours (Spangler and tamento foi o procedimento cirúrgico. O exame histopatológi- Culbertson, 1991). co foi consistente com adenoma das células basais de glândula Clinical signs of are non- salivar zigomática. Sete dias após a cirurgia não foi observado specific. However, owner´s reported swollen, pain, alterações. Um ano mais tarde, o animal retornou para” check- anorexia and exophthalmia (Hammer et al., 2001; up” e foi confirmado que o mesmo apresentava-se saudável e livre de sinais clínicos e laboratoriais de recorrência ou metás- Smrkovski et al., 2006; Johnson, 2008). The differen- tase tumoral. Referências sobre o adenoma de células basais tials diagnostic include sebaceous adenoma (Oh and de glândula salivar zigomática em cães jovens são escassas na Eisele, 2006), clear cell variant of acinic cell carcino- literatura veterinária. De acordo com o conhecimento dos auto- ma (Brunnert and Altman, 1990), epithelial-myoepi- res, este foi o primeiro relato de descrição clínica e cirúrgica do thelial carcinoma (Sozmen et al., 1998), salivary duct adenoma de células basais de glândula salivar zigomática em cão jovem, em Moçambique. carcinoma (Sozmen et al., 1999) and sebaceous carci- (Sozmen et al., 2002). Palavras-chave: Cão, células epiteliais, glândula salivar, tumor. To the authors’ knowledge, reports about basal cell adenoma of zygomatic salivary gland in young *Correspondência: [email protected] dogs are rare in the veterinary literature and no re- Tel.: +55 14 98183-7166

229 Santos I. et al. RPCV (2015) 110 (595-596) 230-232 ports of description of basal cell adenoma of zygo- anaplasia could not be observed. Features were sug- matic salivary gland in a young dog in Mozambique gestive of basal cell adenoma. However, histopatholo- were done. The present case report describes the gical examination was advised to confirm the diagno- clinical and surgery aspects of basal cell adenoma sis and surgical treatment was elected. Bacterial and of zygomatic salivary gland in a dog with 1.2 years fungal culture was negative. old attended at School Veterinary Hospital, Maputo, Patient underwent mass and right zygomatic sa- Mozambique. livary gland extirpation. The dog was premedicated with carprofen (4.4 mg/kg subcutaneous [SC]), mor- Case report phine (0.3 mg/kg SC), acepromazine (0.05 mg/kg SC). Anaesthesia was done with propofol (2.5 mg/ kg An 1.2 years old neutered male Rottweiler dog, intravenous [IV]) and halothane. The animal was pla- weighting 38 kg was attended at School Veterinary ced in left lateral recumbence and a modified lateral Hospital, Maputo, Mozambique, referred for eva- ellipse surgical approach was performed on zygoma- luation of a three months history of swelling of ri- tic salivary gland region and a marginal resection of 3 ght zygomatic region. The owner also reported fast cm of the mass was done and both zygomatic salivary swelling on the first two weeks. No history of trauma gland and mass were removed. A capsule around the was reported and owner´s complaint was related ano- tumour was observed. The skin was apposed with 3-0 rexia. nylon simple isolate sutures (Figure 2A and 2B). Physical examination revealed a well circumscri- bed swelling, measuring approximately 8 cms in dia- meter on right zygomatic region. The swelling was well defined, firm and tender and was fixed to the underlying structures. No pain was revealed but slight pain on either opening of the mouth was observed. Other physical examination parameters were otherwi- se unremarkable. Complete blood count, serum bio- chemistry (alanine aminotransferase – ALT, aspartate aminotransferase – AST, blood urea nitrogen – BUN, Figure 2 - Photography showing a mass in zygomatic salivary alkaline phosphatase, total protein, albumin, globulin gland (white arrows) and capsule (yellow arrow) (a), and skin and creatine kinase – CK) and urinalysis were perfor- sutures (b). med and showed no alteration. Thoracic radiographic Postoperatively, was prescribed cephalexin (25 examination and transabdominal ultrasound were per- mg/kg per os [PO] q12h) for 10 days and carprofen formed and showing no alteration. The radiographic (4.4 mg/kg PO q24h) for 5 days. examination of the head showed an enlargement of Mass sections were fixed in 10% neutral buffered the right zygomatic salivary gland region (Figure 1A formalin, embedded in paraffin, cut through transver- and 1B). sal and sagittal planes in 5 μm thick sections, staining haematoxylin–eosin (H&E) and examined by light microscopy. The mass revealed a white partially en- capsulated soft tissue, measuring 8 cms of diameter. The outer surface was nodular and cut section was lo- bular. Microscopically, the section showed thick bran- ching cords and irregular islands of epithelial cells, with indistinct cell borders, separated by fibrous tis- sue stroma and forming small glandular structures. Nuclei were rounded; with infrequent mitoses and low mitotic rate (Figure 3). Figure 1 - Photograph showing swelling of 8 cm diameters of right zygomatic region (a). Radiographic exam of the head Where observed irregular tumour margins, locally and enlargement of right zygomatic gland region soft tissue infiltrative growth and portions of non-neoplasic sa- (arrow) (b). livary gland tissue. Encapsulation could not be iden- tified. Those findings were consistent with basal cell Fine needle aspiration cytology (FNAC) was done adenoma of zygomatic salivary gland. from the right zygomatic region. Small quantity of Seven days after the surgery, skin suture was re- serosanguineous material was observed. Smear sho- moved and no alteration was observed. One year later, wed cellular smears comprising of neutrophilic cells, the dog returned to check up and confirmed that the erythrocytes and monomorphic and small round-to- dog was healthy and free of clinical signs of tumour oval cells showing few pleomorphism, eosinophil recurrence or metastases by transabdominal ultra- cytoplasm and elongate nucleus. Mitotic figures and sound and chest radiography examination.

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sition for the tumour of the present case report. Benign tumour (Warthin´s tumour) was reported by Pinkston and Cole (1996) as possible and strong re- lation with cigarette smoking. More studies have to be done to confirm the smoking as predisposition factor for salivary gland tumour in young dogs. Clinical signs were similar to the literature (Ham- mer et al., 2001; Smrkovski et al., 2006; Johnson, 2008). The enlargement of the salivary gland can cause exophthalmia which is one of clinical signs of retrob- ulbar disease (Mason et al., 2001). Furthermore, ex- ophthalmia was not observed in the present report case. Basal cell adenomas grow slowly and are not pain- ful in humans (Izutsu et al., 2003). The same was ob- served in the present case report but with slight pain when opening the mouth of the dog. Yerli et al. (2007) reported CT and MRI as more sensitive imaging diagnosing for basal cell adenoma of salivary gland showing de margins of the tumour al- lowing a better surgical plan. In current case report, CT and MRI cannot be done because these exams are not available for animals in Mozambique. On the other hand, radiographic examination of the head showed swelling of the zygomatic region tissue which indicat- ed only soft tissue involvement. The FNAC allowed deciding the treatment because Figure 3 - Photomicrography of zygomatic salivary gland ba- the presence of monomorphic and small round-to-oval sal cell adenoma showing thick branching cords and irregular cells with few pleomorphism, eosinophil cytoplasm islands of epithelial cells, with indistinct cell borders, separated and elongate nucleus and absence of mitotic figures by fibrous tissue stroma (white arrows); and distinct basal cell and anaplasia suggestive of basal cell adenoma. Pres- layer in some regions (black arrows) (H&E) (Bar = 50 µm). Final magnification: x400. ence of neutrophilus and erythrocytes can lead to er- roneous diagnosis (Smrkovski et al., 2006; Gonçalves Discussion et al., 2007). The histopathologic examination was fun- damental for final diagnosis (Smrkovski et al., 2006; The current case report described the clinical and Gonçalves et al., 2007) which identified the basal cell surgical aspects of basal cell adenoma of zygomatic adenoma of the present report case. This type of tu- salivary gland in an 1.2 years old male Rottweiler dog, mour can be mystified with attended at School Veterinary Hospital, Mozambique. which has another treatment (Sozmen et al., 2003). Ba- To our knowledge, the present report was the first sal cell adenoma which is a mixture of basaloid cells, documented in Mozambique. Similar reports in Africa with a distinct basal layer, and larger polyhedral cells, were lack on the veterinary literature. Furthermore, the has similar cytological features of basal cell adenocar- lack of reports regarding to this type of tumour can be cinoma (Sozmen et al., 2003; Mardi et al., 2011) and related to the low prevalence or clinical and histopatho- presence of local invasion has to investigate for ma- logical subdiagnosis. lignancy. The characteristics of benign tumour of the Adenomas of zygomatic salivary gland are rare in current case as presence of thick branching cords and dogs and the incidence is higher in older dogs (Span- irregular islands of epithelial cells, with indistinct cell gler and Culbertson, 1991; Hammer et al., 2001), dif- borders, nuclei rounded and low mitotic rate was simi- fered from the present case, which was observed in a lar of literature (Sozmen et al., 2003; Giudice et al., young dog (1.2 years old). Fibrossarcoma, mast cell tu- 2005). Furthermore, the benign tumour was established mours and lymphomas were reported as more frequent by clinical follow-up findings 1 year after surgery and tumours of salivary glands than basal cell adenomas was observed no tumour recurrence or metastases. (Spangler and Culbertson, 1991; Hammer et al., 2001). Giudice et al. (2005) reported confirmation of benign The aetiology of salivary glands tumours in small tumour 2 years after surgical removal of the tumour. animals is not well defined but genetic factor is sug- Immunohistochemical staining also can be carried out gested in Siamese cats (Hammer et al., 2001). How- to distinguee basal cell from other ever, radiation, smoking, viruses and genetic factor are salivary gland tumours (Sozmen et al., 2003). predisposition factors for tumours in humans (Laane et The treatment was similar that described by Ham- al., 2002). Genetic factor could be a possible predispo- mer et al. (2001), which concerned to remove the af-

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