Kidney cancer metastasizes either lymphatically via retroperitonal lymphatic vessels or via blood to the lungs, liver, bone, and other organs such as the brain, skin, and vagina.
It is not uncommon for the disease to present clinically with symptoms from metastases without primary tumor symptoms. Distant metastases may be solitary, which may be of therapeutic consequence.
Kidney cancer can also grow into the renal vein and further into the caval vein and all along into the right atrium. This form of growth is not considered metastasis, but instead extension of the primary tumor into the vein system. This is very important in terms of treatment.
Around 25% of all patients with kidney cancer will have metastases, most often to bone, lungs, brain, adrenals, and skin at the time of diagnosis (2).