Cancerous tumours of the kidney
A cancerous tumour of the kidney can spread, or metastasize, to other parts of the body. Cancerous tumours are also called malignant tumours. Different types of cancerous tumours can develop in different parts of the kidney.
Renal cell carcinoma
Renal cell carcinoma (RCC) is the most common type of kidney cancer. It starts in the lining of the tubules of the kidney and is found most often in the cortex (the tissue in the body of the kidney).
Types of RCC
There are several types of RCC, including the following.
Clear cell, or conventional, RCC is the most common type of RCC. Most kidney tumours are clear cell RCC. The cancer cells in these tumours are round and filled with clear cellular fluid (called cytoplasm).
Papillary RCC is the second most common type of RCC. The cancer cells in these tumours are shaped like little fingers. Papillary RCC is further divided into 2 types. Type 1 is a low-grade tumour that does not spread very fast. Type 2 is a high-grade tumour that can spread quickly.
Clear cell papillary RCC is a rare, small tumour. They have features of both clear cell and papillary RCCs, so they may have some fluid and some solid parts. Usually only one clear cell papillary RCC develops in a kidney. This type of tumour is usually found in people who have chronic kidney disease.
Multiocular cystic RCC is usually diagnosed around the age of 50. These tumours are made up of many different cysts with thin walls. These cysts are covered by a capsule that separates the tumour from the surrounding normal kidney tissue.
Chromophobe RCC has large, pale brown cancer cells that often look like layers of bricks in a wall. It is usually diagnosed in people between the ages of 50 and 60. Chromophobe RCC has a more favourable prognosis than other types of kidney cancer.
Collecting duct carcinoma is a very rare and aggressive type of RCC. It starts in the ducts at the ends of the tubules in the kidney medulla (the inner tissues of the kidney). It is usually found in younger adults.
Unclassified RCCs are tumours that do not fit into any of the other categories of RCC. The cancer cells look different from any other type of RCC.
Features of RCC
Some RCCs have distinct features (called histological features) that can be seen in the cells when they are examined under a microscope.
Sarcomatoid features means the cancer cells are long and spindle-shaped. RCC with sarcomatoid features usually develops from a clear cell RCC, but sometimes it can start in a clear cell papillary RCC or a chromophobe RCC. They are often high-grade, aggressive tumours.
Rhabdoid features means the cancer cells are shaped like rods. They have large centres (called nuclei) with pockets of fluid in them. RCC with rhabdoid features usually develops from clear cell RCC. They are aggressive tumours with a poor prognosis.
Rare kidney tumours
The following cancerous tumours of the kidney are rare.
Cancer of the renal pelvis starts in the cells that line the renal pelvis of the kidney. These cells are also found along the rest of the urinary tract, including the ureters and bladder. The type of cancer that develops in these cells is called urothelial carcinoma, or transitional cell carcinoma. It is treated like a type of bladder cancer. Find out more about cancer of the renal pelvis.
Renal sarcomas start in the kidney’s connective tissues or blood vessels. Different types of renal sarcomas include leiomyosarcoma, angiosarcoma and rhabdomyosarcoma. They are treated as soft tissue sarcomas.
Renal medullary carcinoma starts in the medulla of the kidney. It is a very aggressive tumour. It is found most often in young people of African ancestry who have sickle cell trait. People with this genetic condition have one copy of the gene that can cause sickle cell disease, but they don’t have the disease.
Primary renal lymphoma is a very rare tumour with a poor prognosis. The most common type is diffuse large B-cell lymphoma (DLBCL).
Primary neuroendocrine tumours of the kidney are very rare. The most common types are small cell carcinoma and large cell neuroendocrine carcinoma. Find out more about the types of neuroendocrine tumours.
Wilms tumour is a type of kidney cancer usually diagnosed in children. It is very rare in adults. Find out more about Wilms tumour.
Referring to or having to do with cancer cells that look and act almost like normal cells (differentiated) and tumours that tend to grow and spread slowly.
A genetic condition that affects hemoglobin (a protein in red blood cells that carries oxygen and gives blood its red colour) and causes red blood cells to have an abnormal crescent (sickle) shape. The abnormal red blood cells can be damaged easily and die quickly, which can cause anemia (a reduction in red blood cells). They can also block small blood vessels, which can cause tissue and organ damage.
Also called sickle cell anemia.
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