Gastric rupture is extremely rare in childhood beyond the neonatal period and the etiology of this condition in preschool children remains obscure. We report a case of 6 year old girl who sustained sudden and lethal gastric rupture. The young patient was affected by Incontinentia Pigmenti (IP), a genetic disease; she had an episode of nausea and vomiting the day before admission to the emergency ward. Abdominal X-ray showed free air in the abdominal cavity, an emergency laparotomy detected a wide perforation of posterior gastric wall. The post-operative course was complicated by a cardiac arrest and an autopsy was performed. Histological examination showed ulcerations and erosions in gastric mucosa with thrombosis in the blood vessel in the submucosa and it suggested Intestinal Neuronal Dysplasia (IND) type B. An eventual correlation between the three diseases that affected our patient was investigated. After a review of literature we have found that the presence of IP not appears to be associated with the other two diseases; so, in our case, it can be considered as a pre-existing pathology. About IND, even if it was never described any case in which this condition has determined gastric rupture, we think, on the basis of clinical and histological findings, that it has determined an increase of pressure at gastrointestinal level, with serious stomach distension until fatal gastric rupture.