title: The pathology of infantile hypertrophic pyloric stenosis after healing.
abstract: BACKGROUND
  Infantile hypertrophic pyloric stenosis (IHPS) is a common surgical affection of unknown etiology. The muscular hypertrophy is known to resolve within a few months after pyloromyotomy (PM). The pathology of IHPS has been studied extensively at the time of PM, but the fate of the pylorus after healing remains unknown.
  
  
  METHODS
  We had the rare opportunity to study two pyloric biopsy specimens obtained 4 months and 2 years (respectively) after an uncomplicated PM for IHPS. They were compared with the initial specimen in one case, with 26 other specimens of IHPS, and with five normal controls. Immunohistochemistry using the avidin-biotin complex (ABC) system was performed for S-100 and nerve growth factor receptor, as markers for the enteric nervous system, and for the tyrosine kinase receptor c-kit, as a marker for the interstitial cells of Cajal (pacemaker cells). NADPH-diaphorase histochemistry was performed as a marker for the neuronal enzyme nitric oxide synthase, which produces the inhibitory neurotransmitter nitric oxide.
  
  
  RESULTS
  In both cases of IHPS, after healing, the circular musculature was not hypertrophic. For all markers studied, the distribution appeared similar to that in the normal pylorus. In contrast, all specimens obtained at the time of PM displayed a severe reduction of the different markers in the hypertrophic musculature.
  
  
  CONCLUSIONS
  The pathological features observed in the circular layer in IHPS appear to resolve within a few months after PM. This suggests that the involvement of the enteric nervous system in IHPS might be milder than generally assumed. The etiology remains obscure, but our occasional observations may provide new insight into the pathophysiology of IHPS, and are in agreement with the excellent longterm clinical outcome for IHPS.
authors.affiliation: Laboratoire de Neuropathologie et de Recherche sur les Neuropeptides, Faculté de Médecine, Hôpital Universitaire des Enfants Reine Fabiola, Université Libre de Bruxelles, Belgium.
authors.forename: J M
authors.initials: JM
authors.lastname: Vanderwinden
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Menu
authors.forename: J L
authors.initials: JL
authors.lastname: Conreur
authors.forename: M H
authors.initials: MH
authors.lastname: De Laet
authors.forename: J J
authors.initials: JJ
authors.lastname: Vanderhaeghen
mesh_terms: D015415:Biomarkers; D001706:Biopsy; D016022:Case-Control Studies; D002675:Child, Preschool; D017615:Enteric Nervous System / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D006984:Hypertrophy; D007223:Infant; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism / Q000473:pathology; D019001:Nitric Oxide Synthase / Q000378:metabolism; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D011707:Pyloric Stenosis / Q000473:pathology* / Q000601:surgery*; D011708:Pylorus / Q000276:immunology / Q000473:pathology*; D017475:Receptors, Nerve Growth Factor / Q000378:metabolism; D016896:Treatment Outcome; D014945:Wound Healing
chemical_list: D015415:Biomarkers; D017475:Receptors, Nerve Growth Factor; D019001:Nitric Oxide Synthase; D019009:Proto-Oncogene Proteins c-kit