Abdominocentesis, rectal examination, thoracocentesis, thoracic percussion, and radiographs will be useful in diagnosis. Chronic obstructive pulmonary disease in the later stages is associated with weight loss. These animals are usually severely dyspneic and reluctant to move. The work of breathing may be so strenuous that the animal does not take sufficient time to eat and maintain body weight. Maldigestion or malabsorption may be caused by the tumor.
Large tumors have significant metabolic demands that consume nutrients.
Gastric neoplasia is not common in horses. Squamous cell carcinomas usually arise at the margo plicatus and can become large enough to obliterate almost the entire lumen of the stomach. Gastric granulomas 2-3 cm in diameter are fairly common in horses and are usually associated with infestations with Habronema larvae. Gastrophilus spp, although do not cause granulomatous disease, can occupy the stomach in large numbers, and are potentials for gastric irritation, causing pain which may in turn result in partial anorexia. Small intestine neoplasia may result in malabsorption and possibly maldigestion.