Ex vivo intracystic contrast studies of multicystic dysplastic kidneys

Classically cysts in multicystic dysplastic kidneys are described as noncommunicating. We determined the accuracy of this hypothesis by performing ex vivo intracystic contrast studies of the typical multicystic kidney and hydronephrotic form of the multicystic kidney.

We evaluated 7 multicystic dysplastic kidneys in patients between 2 weeks and 6 months old using intracystic injection of contrast material, including 4 that were typical and 3 with the hydronephrotic form of multicystic disease. Six and 1 kidneys were evaluated ex vivo and percutaneously, respectively. We obtained images during injection and shortly thereafter.

When contrast material was injected into 1 cyst, it was eventually seen in most of the other cysts in all 7 kidneys. In 6 kidneys discrete ducts were clearly visualized between the cysts. In the hydronephrotic form of the disease these ducts connected to a pelvis-like structure. When evaluated grossly and the cysts were unroofed, a small orifice was noted in each cyst that sometimes admitted a 3.5F feeding tube.

It is generally thought that multicystic kidneys represent a condition with noncommunicating cysts. We believe that the cysts in most multicystic kidneys communicate whether or not a renal pelvis is present.