Extraosseous Metastases and Local Recurrence

Metastatic lesions from kidney cancer are seen in virtually every organ: the lung; pleura; pancreas; adrenal gland; liver; contralateral kidney; bone; lymph nodes; muscles; etc. These lesions can masquerade as another primary tumor. It is important to distinguish metastatic spread of RCC from primary tumors, as this knowledge is essential for the correct diagnosis and for determining the most effective treatment. Imaging studies are essential, as are histopathological examinations. Whole-body spiral CT is currently the method of choice for evaluating the postsurgical nephrectomy site for the presence of recurrent lesions and for detecting the usual anatomical sites of metastases. Like the primary tumor, metastatic lesions tend to be hypervascular and intravenous contrast administration is very useful. Other radiological modalities may be of interest when exploring particular organs, such as US for the liver and MR imaging for the brain and spine. Knowledge of the mechanisms, risk factors, and clinical timing of recurrent disease in surgically treated renal cancer aids the radiologist in understanding and detecting the patterns of recurrence observed on imaging.