Unclassified RCC is a less common type of renal cell carcinoma. It is called unclassified because the cancerous cellsí appearance does not fit in any of the other categories. This type of cancer includes aggressive tumors that do not respond to traditional renal cell carcinoma treatments.
Renal cell carcinoma (also called renal adenocarcinoma or hypernephroma) is the most common type of kidney cancer that develops in adults. It occurs in the cells that line the tubules (small tubes inside the nephrons that help filter the blood and make urine). There are over 1 million nephrons in each kidney. About nine out of 10 cases of kidney cancer are renal cell carcinomas.
Unfortunately, this type of cancer displays mild symptoms in its early stages, and might be misdiagnosed or undetected until the tumor grows larger and has invaded nearby organs.
In addition to unclassified RCC, there are four other types of renal cell carcinoma:
1. Clear cell renal cell carcinoma. This is the most common type of renal cell carcinoma. The cancerous cells appear very pale or clear when examined under microscope. This cancer can be effectively treated with surgery if the tumor is confined to the kidney.
2. Papillary renal cell carcinoma. This is the second most common type of renal cell carcinoma. The cancerous cells form some projections in a finger shape, called papillae, in the tumor. This type of cancer is more common among African Americans and has a good prognosis if treated with surgery in its early stages.
3. Chromophobe renal cell carcinoma. This is the third most common type of renal cell carcinoma. The cancerous cells are similar with the clear cells, they appear pale when viewed under microscope, but they are larger and display different features than clear cells. This type of cancer rarely metastasizes, and the tumors can be successfully removed with surgery.
4. Collecting duct. This is a rare and aggressive type of renal cell carcinoma. The cancerous cells form irregular tubes inside the tumor. Collecting duct carcinoma is more common among young people and unfortunately is diagnosed in most cases when the cancer has metastasized (spread inside the body).