Tumor-containing cells of all three germ layers are called -

All Tumors, benign or malignant, have two basic components → Proliferative neoplastic cells → constitute parenchyma. Supportive stroma → made up of connective tissue and blood vessels. The name of tumor is usually based on the cell, e.g. smooth muscle cell tumor → leiomyoma or leiomyosarcoma, skeletal muscle cell tumor rhabdomyosarcoma. Benign tumors In general, benign tumors are designed by attaching the suffix - oma, e.g tumor of fibroblasts → fibroma, tumor of cartilagenous cells → chondroma. Malignant tumors Malignant tumors arising in mesenchymal cell origin are usually called sarcoma, e.g. fibrosarcoma, liposarcoma, leiomyosarcoma, rhabdomyosarcoma. Malignant tumors of epithelial cell origin are called carcinoma. Carcinoma may be further classified → one with glandular growth pattern, i.e. adenocarcinoma and the other one producing recognizable squamous cells of epithelium, i.e. squamous cell carcinoma. Germ layers and tumor The great majority of the neoplasm is composed of cells representative of a single germ layer. Teratomas, in contrast, are made up of a variety of parenchymal cell types representative of more than one germ layer, usually all three. They arise from totipotent cells and so are principally encountered in the gonads. These totipotent cells differentiate along various germ lines, that can be identified as skin, fat, muscle, tooth structure, hair or any other tissue of the body. An example is a dermoid cyst of the ovary is a benign teratoma (note mature teratoma is benign, while immature teratoma is malignant). Note - There are some exceptions to above general rules, i.e. malignant neoplasms with the suffix - oma → Melanomas, seminoma, hepatoma (hepatocellular Ca), mesotheloma, lymphoma.