What does "left kidney mass" mean?

Left renal mass is a medical term that typically refers to an abnormal space-occupying structure found in the left kidney, in addition to its normal anatomy, during imaging examinations such as ultrasound, CT, or MRI. This condition may be caused by various factors, mainly including: 1. **Renal cysts**: Cysts arise from the outpouching of renal tubules and are mostly benign, rarely becoming malignant. When a cyst is smaller than a certain size (e.g., 4–5 cm), it may not cause noticeable symptoms and usually requires no special treatment. However, if the cyst is large or causes compressive symptoms, further treatment may be necessary. 2. **Kidney tumors**: These include both benign and malignant tumors. Benign tumors include renal fibromas and renal hamartomas, while malignant tumors include renal cell carcinoma and renal pelvis cancer. The nature of the tumor needs to be confirmed through further investigations (e.g., pathological examination), and appropriate treatment measures should be taken based on the specific condition. It is recommended to undergo further diagnostic tests to determine the nature of the mass and formulate an appropriate treatment plan.