Kidney cancer. Coloured scanning electron micrograph (SEM) of the cancerous cells of a Wilms' tumour, a type of kidney cancer. Also known as embryonal carcinosarcoma or nephroblastoma, the condition involves two types of cells: glomerular cells (mainly pink, rounded) and immature spindle cells (mainly orange, flattened). This solid tumour generally affects children, with most cases occurring between 3 and 4 years of age. Often the tumour is painless and so is detected by abdominal enlargement. In most cases, only one kidney is affected. Treatment may involve chemotherapy or radiotherapy, along with surgical removal of the cancerous kidney. Magnification unknown.