Welcome Rogerthat
This is what I found:
milk of calcium: renal cyst
Angiomyolipoma is a benign renal neoplasm composed of fat, vascular, and smooth muscle elements.
Isolated angiomyolipoma occurs sporadically, is often solitary, and accounts for 80% of the tumors.1 The mean patient age at presentation of isolated angiomyolipoma is 43 years, and this neoplasm is about 4 times more common in women than in men.2 Interestingly, 80% of the cases involve the right kidney.1
You could always ask your doctor to explain all of this in layman terms. They do want to check you in 6 months so at least you are being monitored.
Are you having any other health issues?
~Zig