Kidney tumor 4.1cm may be renal vascular smooth muscle lipoma, renal cell carcinoma, nephroblastoma and so on Kidney tumor 4.1cm is the presence of tumor lesion in kidney, with the diameter size of 4.1cm, mainly for the following kinds: 1. Renal vascular smooth muscle lipoma: also known as renal malformation tumor, it is a kind of more common benign renal tumor. It often occurs in the renal cortex. Clinical manifestations are lumbar pain, hematuria, abdominal mass; the main treatment means is surgical resection. 2. Renal cell carcinoma: also known as renal carcinoma, it is a malignant tumor originated from renal tubular epithelial system. It is often solitary. Clinical manifestations include hematuria, lumbago and abdominal mass. Its treatment requires comprehensive staging and other conditions, and surgical resection is usually preferred, such as partial nephrectomy, radical nephrectomy and other surgeries. 3. Nephroblastoma: also known as Wilms’ tumor, is the most common urological malignant tumor in infants and children. Abdominal mass is the most common. Comprehensive treatment, such as surgery combined with chemotherapy, is usually given. It is recommended to go to regular hospitals for comprehensive evaluation, and it is recommended to follow the doctor’s instructions to cooperate with the treatment, and actively standardize the treatment, which can help to improve the quality of life of the patients and prolong the survival of the patients.