Maria Queenan, MD

A 6-year-old female with history of previously resolved iron-deficiency anemia presents to the emergency department (ED) for numerous episodes of nonbloody, nonbilious vomiting and diffuse abdominal pain that began on the day of presentation. She had initially presented to her pediatrician who felt a large left-upper-quadrant abdominal mass and referred her to the ED for further evaluation. She has no associated diarrhea or urinary symptoms. What's the diagnosis?