Catarina Águas, Matilde Ramos Gonçalves, Tiago Moura Rodrigues, Ana Sofia Moreira
Pictographic review of possible locations of renal metastases seen mainly on computed tomography (CT), but also on ultrasonography (US) and magnetic resonance imaging (MRI). Highlight imaging features of renal metastases, raising awareness to the possibility of finding secondary disease in some infrequent places.
Renal cell carcinoma (RCC) has a high incidence, accounting for 3% of all adult malignancies and 90% of adult renal malignancies. RCC can be classified in different subtypes according to histopathology including clear cell, papillary, chromophobe, oncocytic, collecting duct and molecularly defined RCC. The clear cell subtype is by far the most frequent subtype, accounting for 75-85% of RCC, and is also the most aggressive. Once RCC is diagnosed, staging is usually performed by CT to evaluate tumor size, spread to nearby structures, as well as to seek out distant metastatic disease. Renal cell malignant neoplasms have a strong propensity to metastasize. There is a predilection for certain organs and sites including lymph nodes, lung, liver, contralateral kidney, adrenals, brain and bones. However, RCC can be unpredictable, metastasizing to atypical locations, sometimes even several years after a “curative” surgical resection, that may make it difficult to understand if we are dealing with a second primary tumor. Timely recognition of metastatic renal cancer, either by US, CT or MRI, is extremely important, as it impacts clinical management, treatment, and prognosis. Thereby, it is critical that radiologists be aware of potential sites of RCC metastasis, aiding its distinction from primary lesions.
Imaging features of brain metastasis in a patient with right hemiparesis for two days and contrast-enhanced CT of the same patient, performed to identify the primary lesion, revealing a right kidney RCC.
Imaging features of lung metastases in four different patients with RCC.
Imaging features of hepatobiliopancreatic metastases in patients with RCC.
Imaging features of surgical site and adrenal metastasis in patients with RCC.
Imaging features of small bowel, colon and pertitoneal metastasis in patients with RCC.
Imaging features of lymph nodes and vascular metastasis in patients with RCC.
Imaging features of bone metastasis in three different patients with RCC.
As metastatic kidney disease is frequent at initial presentation and even more so on follow-up, adequate image interpretation is extremely important. Imaging allows the evaluation of metastatic disease involving different organs, giving some evidence that helps to distinguish CCR metastasis from primary tumors.