question: My dad 61 yrs old and is diabetic ( type 2). His last check up was in july and all reports were good. 3  weeks ago he experienced pain in his back middle right part and also near his right rib cage. he tried to take muscle pain killer but it didnt improved and pain was persistent for weeks. I sent him for check up and he just got his ultarousnd report today saying they noted a cortical cyst of some measurement in his right kidney.. all the otehr lab test are normal including liver profile. But i am a bit worried about this ultrasound report,, we will see his doctor tomorrow. but i cant sleep now.. ca u tell me more what is this?