Other nonneoplastic lesions
Pyloric stenosis

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 2 November 2018, last major update July 2012

Copyright: (c) 2003-2018,, Inc.

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

Cite this page: Weisenberg, E. Pyloric stenosis. website. Accessed November 18th, 2018.
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

Images hosted on other servers:

Thickened muscularis propria

Hypertrophic pyloric stenosis

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