Presentation
Left loin pain
Patient Data
Non-contrast CT study shows an enlarged left kidney with segmental extensive cystic changes involve its middle and lower zones and sparing its upper pole. These cysts are variable in size as well as density. Some cysts elicit hyperdensity suggesting hemorrhagic cysts and others elicit fluid density consistent with simple cysts. Left proximal ureteric stone with backpressure changes is also noted.
The right kidney appears normal.
A Follow-up contrast-enhanced CT study reveals a stationary course regarding the renal cystic disease with no significant interval changes.No enhancement of these cysts in the post-contrast study. Normal however atrophic renal parenchyma is seen in between the cysts.
Left renal multiple fragmented stones associated with mild dilatation of the left renal collecting system that is abruptly terminated at the upper ureteric segment suggestive of a ureteric stricture possibly secondary to the previous stone.
Normal right kidney apart from few minute cortical cysts.
Case Discussion
Here is a case of localized cystic renal disease that is an uncommon, non-familial, non-progressive disease characterized by clusters of cysts within the normal renal parenchyma. In our case, it is discovered incidentally while assessing the patient's renal colic caused by a ureteric stone. It is stationary for three years denoting benignity of this condition.
Differential diagnosis includes; unilateral autosomal dominant polycystic kidney disease (ADPKD), multilocular cystic nephroma (MLCN), or renal cystic neoplasm.