Congenital segmental dilatation of the duodenum--differential diagnosis for an antenatally-diagnosed intra-abdominal cyst.

We report the third case of segmental dilatation of the duodenum and the first to be diagnosed antenatally. The lesion presented as an intra-abdominal cyst on an antenatal scan at 17 weeks and was followed up with more specific investigations after birth. The final diagnosis was obtained only at laparotomy where the dilated segment was resected. The patient is well at eighteen month follow-up. Segmental dilatation of the gastrointestinal tract, although rare, should be considered in the differential diagnosis of antenatally discovered intra-abdominal cysts.