I have been told I have bilateral extra renal pelvis recently however a year before it was only on the right and they said it could be a 2.3 cm cyst on the right or extra renal pelvis.  Now I am having all this flank pain/rt side pain extremely sharp at times, like a stabbing.  how can you acquire extra renal pelvis over a year I thought it was congenital?
Hi and thank you so much for this query. I am so sorry to hear about this finding. Extra renal pelvis can only be gotten from embryogenesis. This has been there from the time the kidneys were formed. So it all happened when you were still in the womb. It all by itself presents no danger to health. That is most likely not the cause of your pain unless there is something like an infection, stone, obstruction, etc. This should not cause your doctors to stop thinking it is the cause of your symptoms. It is congenital and never acquired. Please, get a second opinion from another urologist/radiologist. The reading of your scans or ultrasounds must be problematic. I hope you find this helpful. Thank you so much for using our services, and please do feel free to ask for clarifications if need be. I wish you the best of health.