Acute appendicitis in neonates: complication or morbus sui generis?

Neonatal appendicitis (NA) is very rare and is associated with a very high perforation rate. Three cases treated at our hospital since 1969 are presented. All of them had a perforated appendix; two represented a complication of an underlying disease, i.e., Hirschsprung's disease and cystic fibrosis, respectively. These diseases should always be ruled out actively in cases of NA. If an underlying disease is not found, NA might be an isolated form of necrotizing enterocolitis limited to the appendix. Histology cannot distinguish between a simple appendicitis and a localized form of NEC, so NA must be regarded as a complication of an underlying disease as well as a morbus sui generis.