[A gastrointestinal stromal tumour of the caecum in a pony with colic].

The research article describes the clinical presentation, diagnostic tests, treatment options, and post-mortem findings of a 25-year-old pony mare that was found to have a rare gastrointestinal stromal tumour (GIST) in the caecum, a part of its digestive system.

Symptoms and Initial Diagnostic Procedures

• The pony initially exhibited symptoms of severe colic, including loss of appetite, lethargy, and an unexplained fever.
• A clinical examination and the insertion of a gastric tube revealed secondary gastric dilation.
• A rectal exploration found a distended and painful caecum, a part of the large intestine, and a dilated, fluid-filled small intestine.
• A solid, mobile, non-painful mass of approximately 10 cm in diameter was detected.
• Ultrasonography of the abdomen revealed a hyperechogenic mass located near the caecum.
• Testing of the peritoneal fluid showed signs of acute to subacute peritonitis.
• Analysis of the pony’s blood found an increased plasma lactate concentration and slight changes in the white blood cell count.

Interventions and Necropsy Findings

• The pony’s condition worsened, showing increased signs of severe pain, even with conservative medical treatment.
• Due to owners refusing surgery and the worsening condition of the pony, euthanasia was performed.
• The post-mortem examination (necropsy) identified adhesion of the caecal apex (the top part of the caecum) to the right and left colon and the ileum (the final section of the small intestine).
• Additionally, a solid mass was discovered in the caecum’s lumen (inner space). This mass was covered with a mucous membrane, had a firm texture, and displayed numerous necrotic and acute haemorrhagic areas. The cut surface of the mass was grey-white to beige and multilobular.

Final Diagnosis

• Based on the histopathological and immunohistochemical tests performed on the tumour, it was determined that the mass was a gastrointestinal stromal tumour (GIST).
• GISTs are rare types of neoplasia (uncontrolled, abnormal growth of cells) that occur in horses, which marked this as a unique case.