A solid mass in the right kidney with well-defined borders and no blood flow signal is usually needed to consider the possibility of occupying tumor growth or kidney stone. 1. Occupying tumor: When there is a local occupying tumor growth in the kidney tissue due to abnormal cell proliferation or tissue hyperplasia, it will be manifested as a local abnormal mass on imaging. When the solid mass on imaging appears to be well defined and no blood flow signal is seen, it is usually necessary to consider a benign tumor of the kidney that is not adherent to the surrounding tissues. However, further biopsy is recommended to determine the benign or malignant nature. 2. Kidney stones: Some patients present with solid kidney masses and need to consider the possibility of kidney stones. When there is localized calcification or stone accumulation in the renal tubules or ureter, it may also appear as a solid mass on imaging, with clear boundaries and no blood flow signal, which can be combined with further imaging to determine the specific cause and location of the lesion. After a solid mass with clear border and no blood flow signal is seen in the kidney, the cause of the disease should be further diagnosed and treated in a timely manner.