Adenocarcinoma is a malignant tumor formed from glandular structures in epithelial tissue. Adenocarcinoma of the stomach, small and large intestine and rectum originates from epithelial lining of gastrointestinal tract. It is an uncommon condition in dogs that can affect any part of the GI system.
Although there is no breed or sex predilection, dogs over six years of age are most commonly affected. The condition holds poor prognosis.
Dogs affected with this condition typically show signs and symptoms that are related to gastrointestinal system and include vomiting, weight loss, poor appetite, abdominal pain, hematemesis (vomiting of blood), melena (black colored feces due to hemorrhage in gastrointestinal system), bright red blood in feces and tenesmus (urgent but ineffective defecation).