A 42 year old man who was recently told that he has hematuri…

A 42 year old man who was recently told that he has hematuria is seen for an abdominal ultrasound. The US is unremarkable except for a 3-cm, well-defined mass with a central scar (spoke-wheel pattern) in the left kidney. On biopsy the lesion was found to be benign.  What is the most likely diagnosis?