Ultrasound in intussusception: a false cystic lead point.

Lead point lesions are very rarely suspected during ultrasound (US) investigation of intussusception. We report a case of idiopathic intussusception where US suggested a cystic lead point. At operation there was no structural abnormality but fluid was noted to be trapped within intussuscepted mesentery. The incidence of 'non-idiopathic' or 'secondary' intussusception is 5-6% with Meckles diverticulum being numerically the most important single entity. The lead point is only rarely identified on ultrasound. A large Chinese series of 377 cases of diagnosis and reduction of paediatric intussusception under US control [1] makes no mention of ultrasonic identification of a secondary cause in any of their cases. A European series of 145 cases [2] noted a causative lesion in 8 (5.6%), of which 2 (lymphoma, intestinal duplication) were identified during the ultrasound study. Adamsbaum [3] recently published a case of an enterogenous cyst as a lead point identified on ultrasound. We present a case with very similar ultrasonic features but which at operation was found to represent fluid trapped within the intussuscepted mesentery rather than a true cystic lead point.