Which type of cancer originates in the cells that line the internal organs and the outside of the body?

Carcinomas are the type of cancer that originates in the epithelial cells, which line the internal organs and cover the outside of the body. These cells are critical as they form the protective layer for organs and structures throughout the body. Carcinomas can arise in various tissues and can affect organs such as the lungs, skin, and digestive tract. Given that they involve the epithelial tissue specifically, their classification is distinct compared to other types of cancer which arise from different cell types or tissues. This makes "carcinoma" the appropriate answer for cancers stemming from epithelial cells.