ICD-11

Any congenital defect of stomach that results from interference with the normal growth and differentiation of the fetus. Such defects can arise at any stage of embryonic development, vary greatly in type and severity, and are caused by a wide variety of determining factors, including genetic mutations, chromosomal aberrations, teratogenic agents, and environmental factors. Most developmental defects are apparent at birth, especially any structural malformation, but some become evident later.

A not uncommon congenital malformation of the stomach of unknown cause in which there is hypertrophy and hyperplasia of the circular muscle of the pylorus. Symptoms of gastric outlet obstruction usually appear between the third and sixth weeks of life. The anomaly is manifested by intermittent vomiting (which increases in frequency and becomes projectile), regurgitation, weight loss, dehydration, electrolyte imbalance, sometimes a small palpable pyloric mass, and visible peristaltic contractions across the epigastrium; there may also be jaundice. Some cases appear to be familial (possibly of autosomal dominant inheritance).