In both dogs and cats, salivary gland tumors are rarely observed, accounting for only <0.2% of the neoplasia in these species1. Due to its low incidence, information regarding primary salivary gland tumors is still limited. This study aims to describe the clinical findings, histopathological diagnosis and therapeutical management of cats and dogs with a diagnosis of neoplasia with salivary gland origin, between 2020 and 2024, in 4 reference centers in Lisbon. Seven cases, 3 dogs and 4 cats were included, aged between 10-15 and 8-13 years respectively, 4 males and 3 females. All cats were domestic shorthair, dog breeds were 1 labrador, 1 golden retriever and 1 mixed breed. In all dogs and half the cats, the mandibular gland was the origin of the neoplasia. In 2 cats, the origin was the minor salivary glands. Regarding the histology adenocarcinoma and carcinoma, were diagnosed in 4 (2 dogs, 2 cats), and 3 (1 dogs, 2 cats) of the cases, respectively. Adenocarcinoma was found in the minor salivary glands. Carcinoma was diagnosed with origin in the mandibular gland in 1 dog and 2 cats.

No metastasis were identified by chest computed tomography or radiography, at the time of diagnosis. Concurrent neoplasia was identified in some animals (2 dogs and 1 cat) but a definitive diagnosis was not established.
 Surgery was performed in 6 animals (3 cats and 3 dogs). Surgery was not pursued in one cat due to the concurrent neoplasia. In this case medical management was provided with toceranib phosphate (2mg/kg EOD). The animal was followed for only 2 more months and lost to follow up. Surgery was the only treatment in 1 dog. In 5 patients (2 dogs and 3 cats) surgery was combined with adjuvant therapy. The protocol included 5 sessions of carboplatin (250 mg/m2), followed by oral cyclophosphamide (10-15 mg/m2) in dogs or oral toceranib in cats with oral meloxicam (0.05mg/kg). One of the cats also received 3 sessions of carboplatin (240 mg/m2) with no response. The dog only submitted to surgery died 9 months postoperatively due to local recurrence and distant metastasis. For patients submitted to adjuvant therapy, at the time of this study, one dog was still alive, 9 months after diagnosis, without signs of local recurrence and one dog survived 26 months after diagnosis. Regarding feline patients, post surgery survival was 5, 7 and 8 months, all with local recurrence.

 This case series provides clinical information and treatment management of patients with salivary gland neoplasia. The mandibular gland is the most frequently affected, in agreement with the literature.2,3 Local recurrence and metastatic disease are frequent, regardless of the treatment. However, surgery combined with adjuvant chemotherapy, and toceranib phosphate was the most consistent approach. Given the small number of cases is not possible to conclude if adjuvant therapy provided survival benefit and, to our knowledge, the use of toceranib phosphate as an adjuvant protocol has not been previously studied. New studies involving a higher number of patients are needed. This work was supported by FCT-Fundação para a Ciência e Tecnologia IP, Grant UIDB/00276/2020 and LA/P/0059/2020-AL4AnimalS. 

References
1. Carberry CA, Flanders JA, Harvey JH, et al. Salivary gland tumours in dogs and cats: a literature and case review. J Am Anim Hosp Assoc 1988; 24: 561–567.
2. Hammer A, Getzy D, Ogilvie G, Upton M, Klausner J, Kisseberth WC. Salivary gland neoplasia in the dog and cat: survival times and prognostic factors. J Am Anim Hosp Assoc. 2001;37(5):478–482. doi:10.5326/15473317-37-5-478
3. Lieske DE, Rissi DR. A retrospective study of salivary gland diseases in 179 dogs (2010–2018). J Vet Diagn Invest. 2020;32(4):604–610. doi:10.1177/1040638720932169