Burning micturation and lower abd. pain.

My mother suffered with burning micturation and lower abdomen pain on and off since 6 months, doing CT scan with contrast-showing left kidney measures 87*55mm, fairly well defined enhancing endophytic lesion seen abutting inferior pole and partially crossing the inter polar line.lesion measures 27*33*29mm(CC*TR*AP) with enhancement and washout similar to the adjacent renal parenchyma in nephrographic and corticomedullary phases.it is causing upward displacement of the lower pole calyces.no evidence of calcification and fat attenuation.deepest point of the lesion measures 25mm from the renal sinus.renal capsule and perinephric planes are normal. -Moderate complexity(Nephrometry grading score-9), advised HPE correlation. -Complex left renal cyst in inter polar region-bosinak 2 This is the report, please advise treatment,and clarify this case is benign or malignant?