Is there anyone who can explain about Mesothelioma?

My knowledge is very poor for this word, the references that I got can not be concluded and its still difficult for me to understand.

Is the Mesothelioma a new type of disease, a symptom of some kind of disease, a type of medicine, a medical devices, or its something related to medical activity, et cetera?

Thankful for your help,
@afrizalnet