What characterizes a carcinoma?

A carcinoma is characterized as a malignant tumor that arises from epithelial tissue, which includes cells that line the surfaces of organs and structures throughout the body. This distinction is crucial because carcinomas can infiltrate surrounding tissues and spread to other parts of the body (metastasize), highlighting their aggressive nature compared to benign tumors, which do not invade adjacent tissues.

Epithelial tissue is the largest type of tissue in the body, forming the skin, and lining internal organs and cavities, making carcinomas a common form of cancer. The processes of uncontrolled cell growth and the ability to metastasize are what primarily differentiate carcinomas from benign tumors.

In contrast, benign tumors, such as those found in connective tissue, do not exhibit malignant characteristics and are generally localized. Additionally, not all tumors, including carcinomas, are always operable - the operability can depend on various factors including the size, location, and extent of the disease. Lastly, many malignant tumors, including carcinomas, tend to grow rapidly and can be invasive, making them quite different from the characteristic slow growth and non-invasive nature of benign tumors.