Is hypertrophic pyloric stenosis a secondary disease?

Hypertrophic pyloric stenosis (HPS) is the most common gastrointestinal obstructive disease in infants which requires surgery. Typical presentation is at 4-6 weeks of life but can present very earlier or congenitally. Here we present 3 cases of HPS which presented in the first day of life with co-existing malrotation, annular pancreas, and duodenal atresia.