Dear friend, welcome to HCM.
if you had a malignant tumour removed last year with partial nephrectomy
, it could very well be the same knid this time also due to microscopic spread. was it in the same upper pole area last year?
they need evaluation and close watch for malignancy again.
benign cysts are very common. but , in your case caution is necessary. better consult your urosurgeon in time.
I hope to have satisfied your query.
keep me posted. good luck !!