I have a 3 cm cyst in my left kidney mid pole with frequent bouts of flank pain (negative for stone ) in addition for the last 3 years there is always blood in my urine ranging from trace to gross amounts, while most kidney cyst are benign there is a history of renal disease in my family and my sister died at 3 months from renal failure , I have been treated for renal artery stenosis and Pyle nephritis, the cyst was 2.5 cm 7 to 8 months ago and my urologist says it s probably a benign cyst come back in 18 months should I get a second opinion ? My dad is in renal failure and my cousin died of liver failure but had renal disease.