Fraley syndrome

Last revised by Arlene Campos on 30 Jan 2024

Fraley syndrome is the eponymous term for a dilated calyx (hydrocalyx) due to compression of a calyceal infundibulum from an adjacent artery or vein.

It is a rare cause of obstruction of the collecting system. Involvement of an upper pole calyx is more common with the right side kidney being more regularly affected. Young women are more frequently sufferers.

The symptoms of Fraley syndrome can vary from asymptomatic microhematuria to severe, recurrent flank pain associated with infections and stone formation.

Imaging findings include:

  • isolated distension and delay in emptying of a calyx (usually the right upper calyx)

  • well-defined horizontal filling defect in the infundibulum - best seen on MIP or 3D reformatted renal excretory phase

  • CT angiogram if performed tracks the vascular path over the kidney, demonstrating a vessel crossing the superior infundibulum and obstructing the superior calyces

In symptomatic patients, surgical correction is indicated. After identification of the artery responsible for the obstruction, the infundibulum is opened, uncrossed from the vessel, and closed by an end-to-end anastomosis.

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Cases and figures

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  • Case 1
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