[Uncommon metastases in renal carcinoma]

Renal clear cell carcinoma (RCCCa) represents 2-3% of the neoplasms in the adult population, and can be metastastatic in up to 30% at the time of diagnosis. In these cases its mortality can be of up to 99% in 5 years, due to the lack of response to current treatments, unless it is a single, surgically resectable metastasis. Currently, there is no explanation for its routes of progression, it even seems to be non existent based on the rare tumor implant sites.

To report unusual metastasis from RCCCa and a review of the literature.

We reviewed retrospectively 15 years of patient records diagnosed with metastasic CaRCC different from: local lymph nodes, lung, bone or liver. We identified 11 cases: brain (2), duodenum (2), tonsils, thyroid, esophagus, diaphragm, testicle, adrenal gland and soft tissue of the knee.

A description of this and other literature series with rare metastasis was done, as well as an analysis of possible routes and mechanisms responsible for the unusual tumor progression in RCCCa. We need to continue investigating the dissemination pathways and other cellular conditions involved in metastastatic kidney cancer in order to better understand and improve the treatment of patients in advanced stages.