RESUMO
An eight-month-old male child presented with a nonpulsatile abdominal mass, which was detected during a routine follow-up examination. After ultrasound examination a tentative diagnosis of pseudoaneurysm of the abdominal aorta was made. An umbilical artery catheterisation had been performed for procuring arterial blood gases after birth for treatment of birth hypoxia. There was a history of fever subsequent to the umbilical artery catheterisation with positive blood and catheter tip cultures for coagulase-positive Staphylococci and Klebsiella pneumoniae. He had also suffered from infectious arthritis of the left hip joint one month after the catheterisation. CT scan with enhancement and angiography confirmed the diagnosis. He was treated successfully with excision of the aneurysm and direct repair of the aorta. A false abdominal artery aneurysm has been noted very rarely as a complication of umbilical artery catheterisation. Such an aneurysm most probably develops from infected thrombi which weaken the aortic wall. Diagnosis may be delayed as the child can remain asymptomatic. CT scan with contrast enhancement can give precise diagnosis. Angiography may be done preoperatively. The safest management is early surgery with direct repair.