Mast cells are granulocytes derived from CD34+ pluripotent progenitor cells that demonstrate plasticity in their development, leaving the bone marrow and differentiating in the tissue where they ultimately reside. They are best known for their role in the allergic response, but also play a prominent immunoregulatory role in other processes, including immune tolerance, the innate immune response, angiogenesis, wound healing and tissue remodeling. Mast cells are found throughout the gastrointestinal tract; their metabolic products influence and regulate intestinal epithelial and endothelial function, gastrointestinal secretion, intestinal motility and absorption, and contribute to host defense. They also play an important role in the development of visceral hypersensitivity through bidirectional interaction with the enteric nervous system. Mast cells have been found to have an increasingly important role in the pathophysiology of a number of pediatric gastrointestinal diseases. This review summarizes the current understanding of the role that mast cells play in the development of pediatric gastrointestinal disorders, including eosinophilic esophagitis, functional dyspepsia, irritable bowel syndrome, celiac disease, inflammatory bowel disease, histologically negative appendicitis, Hirschsprung’s disease, intestinal neuronal dysplasia, and food protein-induced enterocolitis syndrome.

Autoimmune pancreatitis (AIP) is rare cause of abdominal pain in children who often present with obstructive jaundice, mimicking malignancy. An investigation of clinical symptoms, serology, imaging, and histopathology is necessary for diagnosis. We report a 10-year-old female presenting with abdominal pain and jaundice, ultimately found to have AIP after confirmation with tissue pathology. Our patient’s prompt response to corticosteroid initiation is characteristic of this disease state. AIP has 2 subtypes, the second of which is more frequently found in children. Our patient’s pathology did not fit perfectly with either subtype, but had features found in each one. While diagnostic criteria for AIP have not established in pediatrics, our case highlights the combination of clinical symptoms, imaging, and histopathology that children classically present with. While rare, the diagnosis of AIP is associated with comorbidities and must be considered in any child presenting with a pancreatic mass or biliary stricture.

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