Primary nonlymphoid gastrointestinal neoplasms in dogs in Rio Grande do Sul

RESUMO. [Neoplasmas gastrointestinais primários não linfoides em cães no Rio Grande do Sul. ] Neoplasmas gastrointestinais (NGI) são pouco comuns em cães, mas possuem principalmente comportamento maligno e prognóstico reservado. Os tipos de NGI em cães e sua frequência, bem como características epidemiológicas e histopatológicas foram analisados por meio de um estudo retrospectivo dos exames de biópsias de 24.711 cães entre os anos de 2005 a 2017. Adicionalmente, cortes histológicos de NGI foram submetidos à técnica de imuno-histoquímica (IHQ), utilizando os anticorpos anti-pancitoqueratina, vimentina, actina de músculo liso, c-Kit, S-100, CD31, CD79αcy e enolase neurônio específica. Do total de cães analisados, 88 corresponderam a NGI não linfoides. Os neoplasmas ocorreram com maior frequência em cães de raça pura (64,8%, 57/88), machos (53,4%, 47/88), com mediana de idade de 10 anos. O intestino foi acometido em 84,1% dos casos (74/88). Destes, o intestino grosso foi o segmento mais afetado (67,6%, 50/74). A maior parte dos ABSTRACT.Slaviero M. , Argenta F.F. , Ehlers L.P., De Lorenzo C. , Pavarini S.P., Driemeier D. & Sonne L. 2020. Primary nonlymphoid gastrointestinal neoplasms in dogs in Rio Grande do Sul. Pesquisa Veterinária Brasileira 40(1)61-71. Setor de Patologia Veterinária, Departamento de Patologia Clínica Veterinária, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Prédio 42505, Porto Alegre, RS 91540-000, Brazil. E-mail: lusonne@yahoo.com. br Gastrointestinal neoplasms (GIN) are uncommon in dogs, but they mainly show malignant behavior and poor prognosis. The types of GIN in dogs and their frequency, as well as their epidemiological and histopathological characteristics were analyzed through a retrospective study of biopsies from 24.711 dogs from 2005 to 2017. Additionally, histological sections of neoplasms were subjected to immunohistochemistry (IHC) using antibodies against pancytokeratin, vimentin, smooth muscle actin, c-Kit, S-100, CD31, CD79αcy, and neuron-specific enolase. Of the total samples from dogs analyzed, 88 corresponded to GIN. Neoplasms occurred more frequently in purebred dogs (64.8%, 57/88), males (53.4%, 47/88), with a median age of 10 years. The intestine was affected by 84.1% (74/88) of the cases. Of these, the large intestine was the most affected (67.6%, 50/74). Most of the neoplasms had malignant behavior (88.6%, 78/88). Regarding the classification of neoplasms, 46.6% (41/88) of the diagnoses corresponded to epithelial, 46.6% (41/88) were mesenchymal, 5.7% (5/88) were hematopoietic, and 1.1% (1/88) was neuroendocrine. The most frequently diagnosed neoplasms were papillary adenocarcinoma (19.3%, 17/88), leiomyosarcoma (17.0%, 15/88), gastrointestinal stromal tumors (GISTs) (12.5%, 11/88), and leiomyoma (5.0%, 8/88). Adenocarcinomas were located mainly in the rectum, whereas leiomyosarcomas and GISTs developed mainly in the cecum. Epithelial neoplasms showed a greater potential for lymphatic invasion whereas mesenchymal neoplasms appeared to be more expansive with intratumoral necrosis and hemorrhage. Immunohistochemistry was found to be an important diagnostic technique for the identification of infiltrating cells in carcinomas and an indispensable technique for the definitive diagnosis of sarcomas.