How long life after dignose mesothelioma ?

Likely brief: There are some benign mesothelioma/ fibromas. Most are malignant, found late and with invasion, and with limited prognosis even with best care.

Depends: Mesothelioma is a particularly bad cancer to find, with 5 year survival rate generally less than 5%. A lot depends on how it was found, with cancer found due to symptoms (chest pain, shortness of breath, weight loss, etc) doing worse than those found accidentally. If found due to symptoms, survival is generally less than 6-12 months.

Variable: "the average survival times for people with mesothelioma have been between 4 and 18 months. But some people live much longer. Between 5% and 10% of people with mesothelioma live at least 5 years after their cancer is found. These numbers tend to be better for people diagnosed at a younger age." http://goo.Gl/itfp9.