Case Report: Counterclockwise Mesenteric Whirlpool Sign with Left Artery Pseudoaneurysm in a Case of Left Paravertebral Neuroblastoma

Abstract

artery(SMA) with its tributaries cross anteriorly to SMA in clockwise direction. Clockwise whirlpool sign is highly specific and sensitive in representing malrotation/volvulus. As opposed to this, counterclockwise rotation of SMV around SMA can be a normal variant. There have been only seven counterclockwise SMV rotation about the SMA with four of it proven to be negative for malrotation or volvulus.22% of the cases were found to be associated with intra-abdominal pathologies with 31% of them was due to left renal mass.Renal pseudoaneurysm is a rare vascular lesion likely due to under-reported asymptomatic cases. It have an estimated incidence of 5%. This arises when the arterial wall injury of the kidney is tamponade by the hematoma and form fibrosis encapsulating the haemorrhage, which resembles an aneurysmal sac.An unstable pseudoaneurysm can rupture and lead to life threatening haemorrhage. Case Report: A 2 year old girl, presented with fever, left eye bruising and swelling for 4 days. CT Brain and Abdomen noted to have enhancing mass in middle cranial fossa and large left paravertebral mass adjacent to left kidney. Image guided biopsy of the left paravertebral mass was done and proven to be neuroblastoma. Upon reassessment with CT Abdomen after completion of chemotherapy, noted the large left paravertebral mass have reduced in size but there is a pseudoaneurysm involving branches of anterior segment of left renal artery and counterclockwise whirlpool sign of SMV branches . Conclusion :It is important for radiologists to be aware of this normal CT appearance of mesenteric vessels which can be seen to avoid unnecessary laparotomy and increase load of additional investigations in the present era. Renal psudoaneurysm is also an important post renal biopsy complication that should not be miss to avoid life threatening situation.