Nutcracker phenomenon

Case contributed by Dr Safwat Mohammad Almoghazy


Follow-up of buccal mucosal cancer treated by surgery then radiotherapy.

Patient Data

Age: 70 years
Gender: Male

Evidence of compression effect of the left renal vein between the superior mesenteric artery (SMA) and aorta with reduced aortic-SMA angle about 35° (the normal angle is approximately 45°).

Subsequent multiple collateral pathways at the renal hilum: main collateral pathway is the left gonadal vein which will display early enhancement during portal venous phase, suggestive of Nutcracker Phenomenon for clinical correlation to rule out Nutcracker syndrome.

Calcified atherosclerotic changes are seen in the visualized aorta and its major branches.

The penile prosthesis is noted.

No other gross abnormality detected.


It derives its name from the action of a nutcracker which can open a nut by cracking the shell by compressing it between the two handles.

Case Discussion

The nutcracker phenomenon (NCP), also known as left renal vein entrapment refers to a situation of impeded outflow from the left renal vein (LRV) into the inferior vena cava (IVC) as a result of compression and is often accompanied by demonstrable lateral (hilar) dilatation and mesoaortic narrowing. It can be a common incidental finding on routine CT imaging and many patients can be asymptomatic. 

If associated with relevant symptoms, it is then known as the nutcracker syndrome

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Case information

rID: 51924
Published: 11th Jun 2017
Last edited: 6th Jan 2020
System: Vascular
Inclusion in quiz mode: Included