Neoplasia Vs. Tumor
Tumor (Latin for swelling, one of the cardinal signs of inflammation) originally meant any form of swelling, neoplastic or not. Current English, however, both medical and non-medical, uses tumor as a synonym of neoplasm.
Some neoplasms do not form a tumor. These include leukemia and most forms of carcinoma in situ.
Read more about this topic: Secondary Neoplasm