Low-density nodular shadow in the left kidney may be due to the presence of lesions in the left kidney, such as renal cysts, renal tumors and so on. 1. Renal cysts: generally benign lesions, during ultrasound or CT examination, it may be found that there are low-density nodular shadows in the left kidney, in the early stage of the clinical symptoms are relatively mild, with the enlargement of the cysts, symptoms such as lumbar pain, hematuria and so on, if necessary, surgical resection is feasible. 2. Renal tumors: including benign and malignant tumors of kidney, such as renal stenoma, renal cell carcinoma, renal pelvis carcinoma, etc., which may cause low-density nodular shadows in the left kidney when detected. Low-density nodular shadow in left kidney, it is recommended to consult regular hospitals for further examination to clarify the severity of the lesion and standardize the treatment according to the doctor’s prescription.