What are the differences between a benign tumor and swelling?
The term tumor is used in the medical definition of inflammation. However it just denotes a temporary swelling that goes down once the inflammation subsides. This swelling is due to edema (accumulation of fluid). You have to understand that in practice no one uses the term tumor to denote an inflammatory swelling. So the term “tumor” denoting edematous swelling is of historical significance only. 

In modern practice the term tumor is used only to indicate abnormal growth of any kind. Either benign or malignant. 



In pathology an inflammation is classically described as having the following features:


Tumor : Swelling
Dolor : Pain
Calor : Warmth
Rubor : Redness