Segmental dilatation of the intestine in preterm infants: absence of interstitial cells of Cajal in a paired histopathological study.

BACKGROUND: Segmental dilatation of the intestine (SDI) is a rare congenital disorder with unclear pathogenesis. The role of interstitial cells of Cajal (ICC) in preterm infants remains insufficiently defined. We aimed to characterise the histopathological phenotype of SDI, determine its birth prevalence, and explore associations between clinical and histological features and postoperative complications. METHODS: This retrospective single-centre study included preterm infants with clinically suspected SDI who underwent surgery. Resected SDI segments were compared with macroscopically normal resection margins. Histopathological assessment focused on ICC, enteric ganglion cells, and muscular layer alterations. Birth prevalence was calculated for very low birth weight infants below 1500 g. Postoperative complications were defined as mechanical ileus, necrotising enterocolitis, intestinal perforation, or death after resection. RESULTS: Thirty-five infants with SDI were included. Enteric ganglion cells were preserved in all specimens. ICC were absent or markedly reduced in all SDI segments and preserved in all margins. Muscle layer atrophy was present in the majority of SDI segments. The centre-specific birth prevalence was 17.2 per 1,000 very low birth weight infants. Pneumoperitoneum on X-ray, lower birth weight, and submucosal inflammation contributed most in exploratory modelling. CONCLUSIONS: SDI in preterm infants shows a consistent segment-restricted neuromuscular pattern with depletion of ICC, preserved enteric ganglion cells, and muscular layer atrophy. These findings are compatible with a segment-restricted developmental disturbance of the intestinal wall, but the causal role of ICC depletion remains uncertain and requires further investigation in relation to antenatal factors, including placental insufficiency.