Other nonneoplastic

Pyloric stenosis

Last author update: 1 July 2012
Last staff update: 1 September 2020

Copyright: 2003-2023,, Inc.

PubMed Search: Pyloric stenosis[TI] stomach[TIAB]

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Pyloric stenosis. website. Accessed September 26th, 2023.
Definition / general
  • Congenital: common congenital abnormality (1 per 300-900 births)
    • 75% male, onset at 3-12 weeks, high concordance in monozygotic twins, associated with Turner syndrome, trisomy 18, esophageal atresia
  • Acquired: 80% men, hypertrophy of pyloric circular muscle fibers that ends at duodenum
    • Associated with antral gastritis or pyloric ulcer
Clinical features
  • Congenital: persistent projectile non-bilious vomiting in second week of life; regurgitation, visible peristalsis
  • Congenital: pyloromyotomy (splitting of pyloric muscle)
Gross description
  • Congenital: thickened pyloric muscle resembling a fusiform mass, 3-5 cm, that occludes the pyloric channel
Gross images

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Thickened muscularis propria

Microscopic (histologic) description
  • Congenital: edema and inflammatory changes in mucosa or submucosa; thickening primarily of circular muscle, which terminates abruptly distally
Differential diagnosis
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