AbstractBackgroundLactobezoar is a compact mass of inspissated, undigested milk. Most often it is located in the stomach but it may also be located in other parts of the intestine. It is the most common type of bezoar in infancy. Reported herein are two cases of this rare condition mimicking necrotizing enterocolitis.MethodData on two complicated cases of lactobezoar were retrospective analyzed.ResultsThe first case involved a female infant, born at 37 weeks 2 days gestation with a birthweight of 3050 g, and multiple antenatal known congenital defects. Due to esophageal atresia she was given a gastrostomy on the second day of life. After 20 days of continuous feeding with formula feeding she developed food intolerance and clinical signs of a severe sepsis. On examination the abdomen was severely distended and tender at palpation. No palpable mass was noted at examination. Signs of hemodynamic instability and sepsis evolved. Plain abdominal X‐ray showed a pneumatosis of the stomach matching necrotizing enterocolitis (NEC). During emergency laparotomy a gastric bezoar was seen and removed. The postoperative course was complicated by prolonged motility disturbance of the stomach. For a long time she was fed through a jejunostomy. The second case involved a female infant born at 26 weeks 4 days (birthweight 1040 g) who became progressively septic on the day 6 of life. On examination she had a tender and distended abdomen, and abdominal X‐ray showed intra‐abdominal air, consistent with a gastrointestinal perforation. On emergency laparotomy a perforation was seen at the back of the stomach, due to a lactobezoar, with only a little necrosis surrounding it. Surgical treatment consisted of extraction of the lactobezoar and closure of the perforation at the back of the stomach. Two days after the initial surgery, she developed a leakage of the suture anastomosis and another laparotomy was performed. A drain was left near the stomach. After 2 weeks she recovered quickly and feeding was initiated at day 21 with good outcome after 3 months.ConclusionFactors associated with the development of lactobezoar are prematurity, low birthweight, disturbed gastric emptying, hypercaloric and hyperosmolaric milk compositions. It is important to realize that lactobezoar formation can occur in preterm and full‐term infants, receiving either breast milk or formula, even when only minimal enteral feeding is given. Early recognition and treatment of this condition is critical. If a lactobezoar is not detected in an early phase, patients can deteriorate very quickly into a condition mimicking NEC.