A mass of tissue from an overgrowth of epithelial cells in the gastrointestinal (GI) tract is known as a polyp. Polyps are abnormal tissue growths that can occur on the lining of the GI tract, and they are often associated with an increased risk of colorectal cancer, especially if they are adenomatous polyps. These growths can be benign or precancerous, and their removal is often recommended as a preventive measure.
Ulcers refer to open sores or lesions that develop on the lining of the stomach or intestines, typically due to inflammation or infection. Cysts are closed sac-like structures filled with fluid or semi-solid material that can occur in various tissues but are not specifically caused by an overgrowth of epithelial cells in the GI tract. Fissures are small tears or cracks in the lining of an organ, commonly seen in conditions such as anal fissures, but they do not represent an overgrowth of cells.
Therefore, the term "polyp" accurately describes the condition of tissue overgrowth associated with epithelial cells in the GI tract.