Benign Kidney “Lumps” and Cysts
Lumps and cysts are commonly detected in people who undergo ultrasound, CT and MRI scans. Many of these lesions are benign (non-cancerous) and do not require treatment.
Fluid filled cysts are found in between 50-70% of people. Most of these are benign simple cysts though a small proportion are termed complex cysts. Depending on their appearances on a CT scan these complex fluid filled cysts can sometimes be cancerous and need removal.
Another common benign kidney lump/mass is called an angiomyolipoma (AML). These are non cancerous fatty lumps that contain abnormal blood vessels and areas of muscle. They do not usually require treatment unless they cause pain or grow over 4cm in size.