Gastrointestinal stromal tumor (GIST) presenting as a multilocular cystic intra-abdominal mass in a dog.

Background: Gastrointestinal stromal tumor (GIST) is a malignant mesenchymal neoplasm described in humans, dogs, and cats. A hallmark of diagnosis for GISTs is positive immunohistochemical labelling with c-Kit (CD117). The differentiation of GIST from other mesenchymal neoplasms of the gastrointestinal tract is pivotal to allow for initiation of appropriate treatment.