Neoplasm is an abnormal mass of tissue as a result of neoplasia. Neoplasia ("new growth" in Greek) is the abnormal proliferation of cells. The growth of neoplastic cells exceeds and is not coordinated with that of the normal tissues around it. The growth persists in the same excessive manner even after cessation of the stimuli. It usually causes a lump or tumor. Neoplasms may be benign, pre-malignant or malignant. In modern medicine, the term tumor means a neoplasm that has formed a lump. In the past, the term tumor was used differently. Some neoplasms do not cause a lump.