Renal mass - confirm if cancerous?

The patient, 68 years old male with no history of smoking or drinking diagnosed with left lower ureteric stricture with left renal mass with hydronephrosis and hydroureterosis. Also as per previous sonography report, an enlarged prostate and a hyperechoic lesion in left kidney was observed. He showed symptoms of syncope and vertigo, hematuria, fatigue, unresponsiveness. Pathology report mentions presence of blood, bacteria and albumin in urine. And low serum sodium, slightly high serum creatinine and serum CRP. He has previous medical history of high uric acid in blood, diabetes and hypertension. Renal mass biopsy states the following "the sample is predominantly necrotic with scattered atypical cells and high nucleus to cytoplasm ratio, hyper chromatic and pleomorphic nuclei". Please suggest what should be the next steps to diagnose this condition. Doctor suggested FDG PET Scan. Is MM3 Renal scan and DTPA scan helpful to review left kidney function and rule out cancer?