Kidneys/ureters: 0.6 cm left upper pole exophytic renal mass, measuring 98 hu, most likely solid. this was incidental. but wasnt in my ultra sound last month. likelihood this is cancer? dr said rcc, angiolipoma?

I wonder ultrasound and CT were done for what symptom(s). With that character, kidney mass, i.e. malignant lesion, can not be ruled out but it is quite small so you should not worry much at this time. I would suggest a repeat CT of the kidneys with IV contrast in 3 months. By that time, we should have more info about this lesion.

It is not possible to diagnose this accurately without biopsy or surgery. Discuss this with your Urologist. In my opinion it should be explored and removed