53 year-old male here. October 2003 CT showed 2.2 cm simple cyst in midpole of left kidney. Last week, follow up abdominal CT revealed that the cyst has grown into a 4.5 cm x 3.5 cm hypodense structure (1.8 HU). Same kidney was biopsied in 1982 with a diagnosis of glomerulonephritis. Current symptoms are back pain, general fatigue and severe itching in the back/abdominal area. Blood tests indicate a GFR score of 82, sed rate of 5 and a negative ANA result. Increased neutrophils (54 to 72) and decreased lymphocytes (33 to 19) since last CBC in May 2007. WBC count is 8.53, up from 5.63. My family doctor doesn't seem overly concerned. Do I have some type of lymphoma or renal cancer?