School ager with vomiting when eating

CXR and upper GI of achalasia
CXR PA and lateral (above) shows a dilated esophagus with an air-fluid level within it. AP and lateral images from an upper GI (below) show an extremely dilated esophagus with fluid-fluid level within it that terminates in a beak at the gastroesophageal junction.

The diagnosis was achalasia.