I have an anechoic cyst on my left kidney.5*7 mm.it is harmful in my future?

Cyst: You have a cyst that is small and has no internal echoes, suggesting a simple cyst. if worried best option is a repeat Ultrasound in 8-12 moths, most of these tiny cyst are not a cause of concern. The US machine are very sensitive and they can pick up these tiny cyst.

No: Incidental cyst, small, of no consequence. Many people have incidental cysts. They are fairly common on imaging exams, and are nothing to worry about.