Dark spots that appear on kidney ultrasounds can represent cysts, abscesses, abnormalities of the blood vessels,
kidney stones, old calcifications or
kidney cancer.
Cysts on the
kidney are usually harmless and large cysts may need surgical treatment if they are producing symptoms. Each of these condition mentioned above will present will associated symptoms and signs like burning urination, increased frequency of urination, weight loss etc.A CT scan will definitely be helpful.