A 2-year-old girl is brought to the emergency department with intermittent pain in the abdomen that began several hours ago. The patient also had a bowel movement that appeared tinged with blood. Ultrasound shows an area along the ileum in which the proximal small intestine is telescoped into the distal small intestine. Reduction via enema is unsuccessful, and the patient undergoes laparotomy with resultant resection of the involved intestine. The pathologic finding at the lead point is shown in the following image: Which of the following is the most likely underlying diagnosis in this patient?

Question

A 2-year-old girl is brought to the emergency department with intermittent pain in the abdomen that began several hours ago.  The patient also had a bowel movement that appeared tinged with blood.  Ultrasound shows an area along the ileum in which the proximal small intestine is telescoped into the distal small intestine.  Reduction via enema is unsuccessful, and the patient undergoes laparotomy with resultant resection of the involved intestine.  The pathologic finding at the lead point is shown in the following image:  Which of the following is the most likely underlying diagnosis in this patient?

Quizplus · Accepted Answer

11ec160b_3954_258a_9249_03341cff1738_MD0001_00 Intussusception occurs when a proximal segment of intestine telescopes into a distal segment, causing episodes of severe abdominal pain. Progressive intestinal obstruction can also lead to bowel wall ischemia and bloody, currant jelly stools. Most cases are idiopathic in young children; however, 25% have a pathologic lead point for bowel invagination. The lead point is generally an anatomic abnormality (eg, polyp, mass) within the intestinal lumen that is entrapped during peristalsis and forced into distal bowel. Meckel diverticulum is the most common pathologic lead point for intussusception and is a congenital anomaly of the gastrointestinal (GI) tract caused by incomplete obliteration of the vitelline duct. Most Meckel diverticula are clinically silent; symptomatic diverticula often contain ectopic gastric mucosa, which ulcerates and causes painless lower GI bleeding. Patients can also have complications such as diverticulitis, bowel obstruction, perforation, and intussusception. In some cases, Meckel diverticulum may be identified incidentally during laparotomy based on histologic evidence of gastric tissue within the small intestine. Distinct features of gastric mucosa include gastric glands and pits with chief cells and parietal cells. Meckel scan is a nuclear study that can be used to detect the presence of ectopic gastric mucosa and diagnose Meckel diverticulum. (Choice A) Burkitt lymphoma can serve as a pathologic lead point for intussusception, but microscopy would show a lymphoid infiltrate in a starry sky pattern. (Choice B) Intestinal edema and hemorrhage associated with Henoch-Schönlein purpura can trigger intussusception; however, leukocytoclastic vasculitis (perivascular neutrophils with fibrin deposits and nuclear debris) would be expected on microscopy. (Choices C and E) Inflammatory bowel disease (eg, Crohn disease) and pseudomembranous colitis (ie, Clostridioides difficile infection) cause GI tract inflammation that could trigger intussusception, but the incidence is rare, particularly in a child age 2. In addition, microscopic findings of Crohn disease include transmural inflammation with noncaseating granulomas, and pseudomembranous colitis is characterized by pseudomembranes composed of fibrin, neutrophils, and acellular debris. Educational objective: Meckel diverticulum is the most common pathologic lead point for intussusception, a condition in which a portion of the intestine telescopes into itself. Meckel diverticula frequently contain ectopic gastric mucosa, which can aid in diagnosis. __________ References: Clinical characteristics of intussusception secondary to pathologic lead points in children: a single-center experience with 65 cases. (http://www.ncbi.nlm.nih.gov/pubmed/28584905)

A 2-Year-Old Girl Is Brought to the Emergency Department with Intermittent