Abstract
For the last 150 years, cystosarcoma phyllodes of the mammary gland has had 62 different synonyms. At the present time, the most logical name for it seems to be tumor phyllodes. The result of the histological analysis of every single tumor should contain information about the degree of its maturity. The classical description of cystosarcoma phyllodes given by Johannes Müller (1838) is still considered the basis for understanding the clinical and histogenetical aspects of this neoplasm.