RESUMEN
Congenital antral membrane may become symptomatic early in life or late in childhood. A gastric outlet obstruction was revealed in a 14-month-old girl, previously developing well until 3 days ago, by melaena and recurrent non-bilious vomiting, after administration of a non-steroidal anti-inflammatory drug for fever. Plain X-ray performed during the neonatal period was normal. Despite ultrasonography, contrast radiography and endoscopy, the correct diagnosis was made at surgery; the obstruction was due to an inflammatory, thickened membrane with mucosal oedema reducing the central aperture of the diaphragm. This case emphasizes that if antral membrane diaphragm is congenital, the onset of symptoms may result from an additional acquired lesion.