Presentation
Renal dysfunction for work-up. Known carcinoma of the prostate, in remission.
Patient Data
Bilaterally normal renal size, and echogenicity. The right kidney is normal. There is a left renal midpole, exophytic, simple, Bosniak class I cyst. There is an appearance of left-sided hydronephrosis. There is no nephrolithiasis.
( Limited images have been uploaded).
Bilaterally the kidneys are of a normal size and polarity. There are bilateral, simple peripelvic renal cysts, the left greater than the right. These are easily appreciated on the coronal T2 and coronal 3D sequences. The calyces are cupped rather than clubbed; hence, there is no hydronephrosis, especially on the left. As per ultrasound, there is a left midpole, simple, Bosniak class I, exophytic cyst. There is no nephroureterolithiasis and no pelviureteric junctional (PUJ) obstruction.
The MRI of the renal tracts is otherwise normal.
(Limited sequences have been uploaded).
Image courtesy: Dr Amaresh I Ranchod.
Case Discussion
An example of bilateral, simple, renal peripelvic cysts. The volume, appearance and anatomical location of the left-sided cysts mimic hydronephrosis and were reported as such in the ultrasound study.
The right-sided renal peripelvic cysts were not appreciated sonographically and are well identified in the multiparametric MRI study, especially in the 3D coronal reformat.
Peripelvic cysts mimic hydronephrosis (pseudohydronephrosis) and may be incorrectly reported in NECT and ultrasound studies as in this instance. They can even be difficult to interpret in MRI studies, especially within the left kidney in this instance. The identification of cupped calyces versus clubbed calyces assists in diagnosing the presence of peripelvic or parapelvic cysts and the absence of real hydronephrosis.