A diagnostic pitfall: pediatric eosinophilic enteritis with ileal involvement mimicking Crohn’s disease despite nondiagnostic conventional endoscopy—a case report and literature review

Eosinophilic enteritis (EoN) is a rare eosinophilic gastrointestinal disorder that can be difficult to diagnose because symptoms and imaging findings are nonspecific and the mucosa may appear grossly normal. We report an 8-year-old boy with recurrent abdominal pain and intermittent vomiting for more than 4 months. Initial upper and lower gastrointestinal endoscopy was nondiagnostic. Persistently elevated fecal calprotectin and computed tomography enterography showing segmental bowel-wall thickening subsequently raised concern for Crohn’s disease. Peripheral eosinophil counts and serum total immunoglobulin E (IgE) remained within normal ranges. Because symptoms and objective evidence of intestinal inflammation persisted, transanal double-balloon enteroscopy (DBE) with ileal biopsies was performed. Histopathology showed spatially heterogeneous eosinophilic infiltration of the ileal lamina propria, with approximately 20 eosinophils per high-power field (HPF) at 15 cm and 70 eosinophils/HPF at 5 cm proximal to the ileocecal valve; no granulomas or crypt architectural distortion were identified. Secondary causes of intestinal eosinophilia were systematically evaluated, supporting EoN with histologically confirmed ileal involvement. The patient improved clinically after combined dietary, nutritional, and systemic corticosteroid treatment. This case highlights that grossly normal mucosa and patchy histological involvement can make conventional evaluation nondiagnostic. Persistent gastrointestinal symptoms accompanied by objective inflammatory or radiologic abnormalities should prompt repeat small-bowel assessment with adequate histological sampling.