Carcinoma is the clinical term for cancer of epithelial cells, which are cells that line the organs and form the top layer of the skin. The American Cancer Society reports that carcinoma is the most common type of cancer, accounting for approximately eight out of every 10 cases of cancer in the United States. There are many different types of carcinoma, which are named based upon what organ or specific cell type is affected.
Lung Carcinoma
Lung carcinoma is a very serious and potentially aggressive type of cancer, involving the transformation of epithelial cells that line the lungs. Lung carcinoma is further classified into two subtypes: small cell and non-small cell carcinoma, which are named based on the appearance of the cancer cells when examined under a microscope. Merck Manuals, an online medical library, reports that 85 percent of cases of lung carcinoma are related to smoking cigarettes.
Renal Cell Carcinoma
The National Cancer Institute reports that renal cell carcinoma is the most common type of kidney cancer. The cancer begins in the epithelial layer of cells that line the renal tubules, which filter blood in the kidneys. Advanced kidney cancer can cause so much tissue destruction in the kidneys that they stop working properly, or not at all. Like other cancers, if the cancer metastasizes, or spreads, the cancer is much more difficult to treat.
Squamous Cell Carcinoma
Squamous cell carcinoma is one type of skin cancer, stemming from thin and flat squamous cells, which reside in the uppermost layer of the epithelium in the skin. Squamous cell carcinoma makes up about 20 percent of skin cancer cases in the United States, according to the American Cancer Society. The risk of developing this type of cancer is increased in persons whose skin is regularly exposed to the sun without sunscreen.
Basal Cell Carcinoma
This is the most common type of skin cancer, and is diagnosed in eight out of every 10 cases of skin cancer, according to the American Cancer Society. Basal cells reside in the bottom layer of the skin epidermis. This is a slower growing and less aggressive form of skin cancer than squamous cell carcinoma, meaning it does not grow or spread as fast.
Merkel Cell Carcinoma
Merkel cell carcinoma, which is also called neuroendocrine carcinoma of the skin, is a rare type skin cancer. The Mayo Clinic reports that Merkel cell carcinoma is also associated with long-term sun exposure, but may also affect people with weakened immune systems, such as people with HIV/AIDS. The cancer cells of Merkel cell carcinoma usually appear the same color as the skin, or may form a reddish-blue nodule. The skin most often affect is that of the head, neck or face.
