Spontaneous intestinal melanoma in dogs.

Primary melanoma of the gastrointestinal tract is a rare, highly malignant neoplasm that is associated with an unfavorable long-term prognosis. Animal studies are needed to further characterize this tumor and to develop new and more effective protocols. A spontaneous canine intestinal melanoma is described which, because of its local aggressive behavior and advanced stage, was not treatable with conventional strategies, thus being a potential candidate for investigational trials.