BACKGROUND & AIMS: The interstitial cells of Cajal form a network in close association with the smooth muscle of the gut. They are regarded as pacemaker cells and might be involved in motility disorders. Their distribution was studied in a common disorder with a dysfunction of the pyloric sphincter called infantile hypertrophic pyloric stenosis. METHODS: Specimens from 27 infants with pyloric stenosis and 12 controls were processed for immunohistochemistry using a specific antiserum raised against c-kit, a tyrosine kinase receptor expressed by interstitial cells. RESULTS: In the normal pylorus, numerous interstitial cells were labeled throughout the tissue. In pyloric stenosis, c-kit immunoreactivity was absent in the major part of the tissue. Interstitial cells were observed only in the inner part of the musculature, near the submucosal edge, and in the antrum, at the proximal end of the biopsy specimens. CONCLUSIONS: The lack of interstitial cells in the pylorus possibly contributes to the motility disturbance of infantile pyloric stenosis. (Gastroenterology 1996 Aug;111(2):279-88)

Allgrove's syndrome, i.e., achalasia, addisonianism, alacrima (OMIM 231550) is an autosomal recessive disorder recently associated with the AAAS gene coding for the Aladin protein. However, the pathophysiology of achalasia in Allgrove's syndrome remains obscure. Here we investigated the histopathology of the cardia in Allgrove's syndrome. Myectomy specimens from 10 children with Allgrove's syndrome and four normal cardia were studied by routine staining and by immunohistochemistry for the pan-neuronal marker PGP9.5, neuronal NO synthase, interstitial cells of Cajal, and CD3+ lymphocytes. In the normal cardia, myenteric ganglia, intramuscular nerve fibers, and interstitial cells of Cajal were numerous, whereas myenteric fibrosis and lymphocyte infiltrates were absent. In Allgrove's syndrome, fibrosis of the intermuscular plane was prevalent in all patients. Myenteric ganglia were absent, decreased, or apparently normal in 1 of 10, 8 of 10, and 1 of 10, respectively. Neuronal NO synthase was absent in 7 of 10 and decreased in 3 of 10, whereas interstitial cells of Cajal appeared normal in 7 of 10 and decreased in 3 of 10. Lymphocytes infiltrating the myenteric plexus were present in 6 of 10. Pyloromyectomy specimens available for six patients showed normal histopathologic features. In conclusion, the lack of neuronal NO synthase and fibrosis of the intermuscular plane can be linked to the defective cardia relaxation. Other features were less constant and may reflect the variability of disease expression and progression among patients with Allgrove's syndrome.