Types of Carcinoma

Carcinoma is a cancer that originates in epithelial tissue cells. These cells are present both in the skin (epidermis) and in the lining of internal organs. Different types of carcinoma can be classified by their location and stage. Adenocarcinoma is a carcinoma originating in glandular epithelial cells, while carcinoma-in-situ and invasive carcinomas refer to earlier and later stages of cancer respectively. Some of the most common types of carcinoma include invasive ductal carcinoma, responsible for skin cancer, and basal and squamous cell carcinoma, which both produce skin cancer.

Adenocarcinoma

• An adenocarcinoma is a carcinoma that originates in glandular tissue, or tissue responsible for the production a secretion of a substance. The breast ducts and lobules are examples of glandular tissues where adenocarcinomas may sometimes develop.

Carcinoma-in-situ

• Carcinoma-in-situ describes an early stage of cancer. It is marked by the confinement of the cancer to the thin layer of cells in which it began. Carcinoma-in-situ indicates that cancer cells have not yet metastasized, or spread to other organs in the body.

Invasive Carcinomas

• Invasive or infiltrating carcinomas describe cancer cells that have spread beyond their places of origin, and have begun to infiltrate other organs. Most types of breast cancer are invasive carcinomas.

Invasive Ductal Carcinoma

• According to the American Cancer Society, invasive ductal carcinoma, or IDC, is the most common form of breast cancer. IDC begins in the ducts or milk passages of the breast, and then breaks through the ductal wall and spreads into the breast's fatty tissue. Once in the fatty tissue, the cancer has the potential to metastasize and travel through the bloodstream or the lymphatic system.

Basal Cell Carcinoma

• According to the American Cancer Society, basal cell carcinoma accounts for 80 percent of skin cancer cases. This carcinoma usually originates in sun-exposed areas, like the back of the neck or shoulders. Basal cell carcinoma is generally slow growing, and rarely metastasizes. However, without the proper treatment it can spread to other areas, or invade bones and tissues below the skin. According to the American Cancer Society, up to 50 percent of those diagnosed with one basal cell carcinoma will develop a new one within five years.

Squamous Cell Carcinoma

• The other 20 percent of skin cancers -- according to the American Cancer Society -- are Squamous cell carcinomas. They often appear on the neck, face, ears, lips and the back of the hands, however they can also form in skin ulcers or scars anywhere on the body. Unlike basal cell carcinomas, squamous cell carcinomas are generally aggressive and are more likely than basal cell carcinomas to metastasize and spread to distant locations in the body.