A case study of pyelolymphatic backflow demonstrated on CT

Abstract

Pyelolymphatic backflow is a rare type of pyelolymphatic fistula that occurs in cases of urinary obstruction. This phenomenon may help to decompress an acutely obstructed kidney, and therefore, alleviate renal function from deteriorating. Pyelolymphatic backflow has specific imaging characteristics best shown on CT urography. Our case study aims to improve the understanding and diagnosis of pyelolymphatic backflow by presenting a case of pyelolymphatic backflow seen on CT urography, including discussions on the pathophysiology, clinical relevance and management of this phenomenon. Our case study demonstrates the opacification of landmark lymphatic structures including the retroperitoneal para-aortic lymphatic chain, cisterna chyli and thoracic duct, which have not been demonstrated previously.

Keywords: Computed tomography; Pyelolymphatic backflow; Pyelolymphatic fistula.

Fig. 1

(a, b) Axial CT urography in the excretory phase. (c, d) Coronal CT urography in the excretory phase. The orange arrows denote the opacified lace-like pararenal lymphatics. The red arrows denote the opacified para-aortic lymph node chains. Black asterisks denote the opacified urinary tract.

Fig. 2

Coronal CT urography in the excretory phase. The blue arrow denotes the opacified cisterna chyli and yellow arrow denotes the opacified thoracic duct. Black asterisks denote the opacified urinary tract.

Fig. 3

3D reconstruction of the urinary tract and lymphatic network. The orange arrows denote the opacified lace-like pararenal lymphatics. The red arrows denote the opacified para-aortic lymph node chains. The purple arrow denotes the right lumbar trunk and the pink arrow denotes the left lumbar trunk. The blue arrow denotes the cisterna chyli and yellow arrow denotes the thoracic duct.