Many people will find the presence of renal malformation tumor when they have kidney ultrasound. Renal misshapen tumor is actually a kind of lipoma on top of the smooth muscle of the kidney blood vessels, it belongs to a benign tumor, which is a kind of kidney tumor caused by the abnormal proliferation of kidney blood vessels. It is a benign tumor caused by the abnormal proliferation of blood vessels in the kidney. Renal malformation tumor lacks specific manifestations and may be asymptomatic when the tumor is small, and most patients are often found accidentally by ultrasound or CT examination during physical examination or other reasons. If the tumor bleeds internally, sudden local pain may occur; if the large tumor ruptures and bleeds, acute back and abdominal pain, hypovolemic shock, hematuria and abdominal masses may occur. Although renal malformation tumor is a benign tumor, if the size exceeds 4 cm, it will still affect the kidney function, and a small portion of malformation tumors may become malignant or cancerous. Therefore, if a malignant tumor is found during a medical checkup, it should not be taken lightly. If the size of the tumor is small, it should be followed up regularly, and if the size is larger than 4 cm, it should be treated promptly. Most of the misshapen tumors have no obvious symptoms, but if the size of the tumor is large and it ruptures suddenly for various reasons, it can cause massive bleeding in the body and even cause shock and death. Therefore, people with malignant tumors should be careful not to do strenuous exercise or heavy physical work. The exact cause of renal malformation is not well understood, but it may be related to genetic factors and various pathogenic infections.