A case of Meckel's diverticulum misdiagnosed as gastrointestinal stromal tumor: case report and literature review.

Meckel's diverticulum (MD) is a common congenital gastrointestinal malformation often containing ectopic gastric mucosa. It is prone to ulceration and painless lower gastrointestinal bleeding, predominantly affecting children and adolescents. Gastrointestinal stromal tumors (GISTs), which arise from Cajal interstitial cells, are predominantly mesenchymal tumors that occur predominantly in middle-aged and elderly individuals. Both conditions may occur in the small intestine, presenting gastrointestinal bleeding and exhibiting overlapping imaging features, which pose challenges for clinical differentiation. This report describes a 17-years-old female patient admitted to the First Hospital of Jilin University with intermittent melena, abdominal pain, and anemia. Small bowel CT imaging (CTE) revealed a nodular lesion measuring approximately 0.9 cm × 1.8 cm within the ileal lumen. The lesion exhibited a broad base attached to the intestinal wall and showed marked homogeneous enhancement, strongly suggesting a GIST. Previous gastrointestinal endoscopy had only indicated chronic gastritis and colitis. The patient underwent laparoscopic segmental resection of the ileal mass. Postoperative pathology confirmed an MD with fundic gland-type ectopia. This case highlights the diagnostic challenges of complex MD and underscores the critical role of histopathology. It thereby provides diagnostic and surgical guidance for MD cases that mimic GIST on imaging, thereby reducing misdiagnosis.