Case 1: resection of a huge right kidney tumor (500px in diameter) First, the right kidney tumor specimen: Case presentation: Female patient, 41 years old. She was admitted to the hospital with “intermittent pain in the upper abdomen for more than 1 month”. Physical examination: a hard mass could be found in the right abdomen, which could not be pushed, and there was pressure pain. Ancillary examination: (outside hospital) CT: right kidney giant vascular smooth muscle lipoma with hemorrhage and rupture. After the patient was admitted to the hospital, he underwent embolization of the right kidney tumor in the interventional department first, and then received surgical treatment in our department. The operation was very smooth, with an intraoperative bleeding of about 120 ml. Postoperative pathology: right renal vascular smooth muscle lipoma. What is angiosmooth muscle lipoma? Renal malformation tumor is a benign tumor, because it is composed of blood vessels, smooth muscle and fat, so it is also called “smooth muscle angiomyolipoma”. Larger malformation tumors may distort and displace the renal calyces in one or more places, affecting urinary drainage, which may cause damage to kidney function. In addition, because the tumor tissue is rich in blood vessels, it is easy to bleed. Intra-tumor bleeding may cause severe pain, and if it ruptures into the renal calyces, it can cause massive hematuria, which is life-threatening and requires early surgical removal. Some of the misshapen tumors are very similar to renal cancer in morphological manifestations and are not easy to distinguish. Approximately 1% of vascular smooth muscle lipomas have malignant manifestations, and the pathological name is epithelioid vascular smooth muscle lipoma, which requires clinical vigilance.