Acute abdomen due to a perforated giant GIST of the small intestine evolving slowly for 6 years: A case report.

Background: Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms, comprising less than 1 % of gastrointestinal tumors. Arising from interstitial cells of Cajal, GISTs are frequently found in the stomach and small intestine. Typically asymptomatic, GISTs can occasionally present as acute abdominal emergencies, including hemorrhage, obstruction, or perforation. This report presents a case of spontaneous perforation of a large ileal GIST, leading to peritonitis.

Methods: An 82-year-old man arrived at the emergency department with severe abdominal pain, fever, vomiting, and diarrhea. Physical examination showed abdominal tenderness and distension, and laboratory findings indicated elevated inflammatory markers. A computed tomography (CT) scan revealed a 15 cm mass in the lower right abdomen, with free fluid and extraluminal air suggesting perforation. Emergency laparotomy confirmed a perforated tumor, with purulent peritonitis. Surgical resection of the affected ileum and cecum was performed, followed by anastomosis and enterostomy. Histopathology confirmed a high-risk GIST, and the patient recovered well post-operatively, subsequently beginning adjuvant imatinib therapy.

Conclusions: GISTs commonly remain asymptomatic until complications arise. Peritonitis due to tumor perforation is rare and necessitates prompt surgical intervention. Surgical resection remains the standard treatment for localized GISTs, with adjuvant imatinib recommended for high-risk cases. CT imaging is critical for diagnosis and surgical planning. Conclusions: While GIST perforation leading to peritonitis is rare, it requires urgent surgery. High-risk GIST patients benefit from adjuvant imatinib and should undergo long-term follow-up. This case highlights the importance of a multidisciplinary approach for complex GIST presentations and associated complications.