Hello , I am not sure how to answer your question. However with your husband having test and all this is a good start to finding what is going on now. My father had a mass in and out of his kidney and did not know what it was until they removed it. The thought was cancer but they could not say without the tumor to say for sure. Please let us know how the test turn out.
Best of luck and thoughts and prayers are with you and your husband.
A Friend Wendy