Pathological findings of benign tumors are indicated by the addition of “tumor” to the tissue or cell type. For example, from the gastrointestinal tract glandular epithelium, called adenoma, including tubular adenoma, choriocarcinoma; from the smooth muscle, called smooth muscle tumor. Only a few benign tumors are not named according to this principle, such as chondroblastoma, osteoblastoma, hemangioblastoma. Tissue sources of benign tumors include epithelial tissues, such as squamous epithelium of the skin and mucous membranes, adenoepithelium of the mucous membranes of the gastrointestinal tract, and columnar epithelium; mesenchymal tissues, such as fibrous tissues, smooth muscles, rhabdomyosarcomas, blood vessels, and lymphatic vessels; and also lymphohaematopoietic and neural tissues.