Carcinoma is a type of cancer that begins in the cells of the skin or tissues that line or cover internal organs. It occurs when these cells grow uncontrollably, forming tumors that can invade nearby tissues. There are several types of carcinoma, including adenocarcinoma, which originates in glandular cells, and squamous cell carcinoma, which arises from flat cells. This disease can affect various parts of the body, such as the lungs, breasts, and colon. Early detection is crucial for effective treatment, which may include surgery, radiation, or chemotherapy. Understanding the signs and risk factors can help in prevention and timely intervention.