HYPERTROPHIC PYLORIC-STENOSIS - ULTRASTRUCTURAL ABNORMALITIES OF ENTERIC NERVES AND THE INTERSTITIAL-CELLS OF CAJAL

Dysfunction of pyloric inhibition has been implicated in the pathophys iology of hypertrophic pyloric stenosis. Normal inhibition likely is m ediated by peptideric enteric nerves and also may involve interstitial cells of Cajal (ICC). The authors used electron microscopy to qualita tively assess these structures in infants with pyloric stenosis and in normal controls. Pyloric muscle strips from five infants with hypertr ophic pyloric stenosis, from three normal pediatric organ donors. and from three adults were examined. The following observations were made. (1) Muscle cells were primarily in a proliferative phase in pyloric s tenosis and exibited very few gap junctions between smooth muscle cell s or ICC compared with the control specimens. (2) The circular muscle layer in pyloric stenosis was characterized by near absence of large g ranular vesicle-containing nerve fibers compared with the control spec imens. (3) There were fewer nerve cell bodies in the myenteric plexus in pyloric stenosis, and the total number of ganglia was lower than th at in control samples. (4) Interstitial cells of Cajal were almost com pletely absent in patients with hypertrophic pyloric stenosis, but the re was a group of cells resembling ICC that was termed !CC-like cells. These cells may represent a failure or delay in the maturation proces s of the ICC. These findings show that there are significant structura l abnormalities of the inhibitory nervous system in hypertrophic pylor ic stenosis. The ontogenic origins and functional significance of thes e results require further investigation. Copyright (C) 1995 by W.B. Sa unders Company.