_1728186807 20241006035327000 Rovedar Daryoushbabazadeh@gmail.com Rovedar Small Animal Advances Small Anim. Adv. 2821-2363 09 04 2024 3 3 Ensiye Sajadian Jaghargh Ali Mirshahi Hanieh Shaterzadeh Yazdi Introduction: Mast cell tumors (MCTs) have been described as a form of cancer affecting a specific type of blood cell that typically plays a role in the body's reaction to allergens and inflammatory processes. The MCTs have been classified as skin tumors in dogs which can also affect other areas of the body, such as the spleen, liver, gastrointestinal tract, and bone marrow. The present study investigated the clinical and histological signs, biological behavior, and treatment of primary oral mast cell tumors. Case report: A 3-year-old neutered female, weighing 18 kg and classified as a medium mixed breed, was referred to a veterinary clinic in Mashhad (Iran) due to the presence of a pink, lobulated mucosal mass located on the internal surface of her lower lip. Although the vital signs were normal, clinical examination, radiology, and an incisional biopsy were performed from the lesion site under general anesthesia for histology study. Histopathological features were similar to those of mastocytoma in this case. On presentation, no concurrent mass was found on other sides of the body. Mandibular lymph nodes were not enlarged; however, the incisor teeth of the mandible were loosed. Accordingly, the primary oral MCTs were diagnosed. The surgery was done and After a follow-up period of 150 days post-excisional surgery for a Mast cell tumor, the patient remained alive and exhibited no visible signs of tumor recurrence or surgical complications. Conclusion: The current case report defined a primary Mast cell tumor with slow tumor growth and without metastasis in the mucosal surface of the lower lip in a dog treated by complete excisional surgery only, unlike some previous studies of primary oral MCTs in dogs with aggressive biological behaviors.        09 04 2024 22 26 https://creativecommons.org/licenses/by/4.0 10.58803/saa.v3i3.24 https://saa.rovedar.com/index.php/SAA/article/view/24 https://saa.rovedar.com/index.php/SAA/article/download/24/54 https://saa.rovedar.com/index.php/SAA/article/download/24/54 10.1080/01652176.2004.9695178 10.2147/VMRR.S41005 Khoo A, Lane A, and Wyatt K. Intranasal mast cell tumor in the dog: A case series. Can Vet J. 2017; 58(8): 851-854. PMID: 5508967 10.2460/javma.251.4.421 10.1111/vco.12071 10.1186/2052-6687-2-1 10.5326/JAAHA-MS-5557 10.1177/030098588201900603 10.1111/avj.12693 Linde KJ, Stockdale SL, Mison MB, and Perry JA. The effect of prednisone on histologic and gross characteristics in canine mast cell tumors. Can Vet J. 2021; 62(1): 45-50. PMID: 33390598 Radlinsky M, and Fossum TW. Small animal surgery textbook. 5th ed. Philadelphia: Elsevier Health Sciences; 2019. p. 337-338. 10.2460/javma.237.8.936 10.1111/j.1939-1676.2003.tb02501.x 10.1016/j.jcpa.2014.07.004 10.1053/j.ctsap.2005.12.016 Khodakaram-Tafti A, Eshraghi M, Geramizadeh B, Shaterzadeh-Yazdi H, and Taghipur-Bazargani T. Immunohistochemical and morphopathological features of multiple cutaneous mast cell tumor in a cow. Braz J Vet Pathol. 2015; 8(2): 68-71. Available at: https://www.bvs-vet.org.br/vetindex/periodicos/brazilian-journal-veterinary-pathology/8-(2015)-2/immunohistochemical-and-morphopathological-features-of-multiple-cutane/ 10.1111/j.1939-1676.1999.tb02217.x 10.1111/j.1939-1676.1994.tb03259.x 10.1158/1078-0432.CCR-08-1860 10.2460/javma.20.09.0488