Background: Annular pancreas is a rare congenital anomaly that can present beyond the neonatal period and may be overlooked, especially when early imaging is normal. Its obscure clinical presentation may mislead clinicians toward non-surgical diagnoses, delaying correct identification of structural gastrointestinal anomalies.Case Presentation Summary: An 8-month-old girl presented with chronic vomiting fluctuating between 2 and 6 episodes per day, forceful, and mostly consisting of milk. In the neonatal period, she had intractable vomiting. An upper GI series excluded obstruction, and dynamic intestinal obstruction was presumed. Vomiting decreased to 2–3 episodes daily and did not initially impair growth.At 2 months, during hospitalization for bronchiolitis, marked hypereosinophilia (up to 4,000/μL) and persistent vomiting raised suspicion of cow’s milk protein allergy. Breastfeeding was continued, and standard formula was replaced with a hydrolyzed one, but vomiting persisted.At 6 months, the child developed coffee-ground vomiting. Endoscopy showed erosive gastritis and duodenitis; histology revealed significant mucosal eosinophilic infiltration. Eosinophilic gastroduodenopathy was diagnosed, and treatment with topical budesonide was initiated.One month later, she re-presented with worsening vomiting, melena, and anemia (Hb 7.5 g/dL). Abdominal X-ray, ultrasound, and surgical examination revealed no pathology. During a second endoscopy, after 5 hours of fasting, the stomach was found full and near aspiration. This prompted a repeat upper GI series, which showed obstruction at the descending duodenum. Surgical intervention identified an annular pancreas encircling the duodenum, and gastrojejunostomy was performed.During 7 years of follow-up, the child remained asymptomatic with normal growth.Learning Points / Discussion:- Chronic vomiting in children, especially in infants, requires thorough medical evaluation to exclude anatomical abnormalities as a possible cause, including annular pancreas.- Teamwork is essential for the timely diagnosis of such complex cases.
