Hello,
Complex renal cysts have a variety of irregularities in them and also within the content inside it. The lining can be thin or thick and many times thick wall lining of the cysts leads to kidney cancer. In such cases, renal biopsy is one of the best method to decide the mode of treatment.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.
A urologist or nephrologist would help you with your kidney issue. A gynecologist would see you if it was an ovarian cyst. Perhaps your doctor misspoke. It happens.