Complex kidney cyst

My husband recently had an ultrasound after he had visible blood in his urine. A follow up test found traces of blood, although nothing was visible to the naked eye. His doctor ordered an ultrasound. The ultrasound report says:

cluster of parapelvic right renal cysts vs. complex cyst measuring up to 15 mm.

The doctor has ordered an MRI of the abdomen with, and without contrast, but he was not able to get an appointment for about two months. How concerned should I be? Thank you!