After discussing about malignant mesothelioma now let us learn about the benign mesothelioma.

It is important not to confuse malignant mesothelioma with benign tumors that also start in the mesothelium.
Adenomatoid tumor

This benign tumor can develop in the mesothelium of certain female and male reproductive organs. In men, it often starts in the epididymis (a small collection of ducts that carry sperm cells out of the testicle). In women, this tumor may begin in the fallopian tubes (tubes that carry eggs from the ovaries to the uterus or womb).
Benign cystic mesothelioma

This is another non-cancerous tumor that may begin in mesothelium near female reproductive organs.
Solitary fibrous tumor of the pleura

This type of benign tumor can form in the pleura surrounding the lungs. It used to be called benign fibrous mesothelioma, but doctors now know that this tumor actually starts from tissue under the mesothelium and not from mesothelial cells. This disease is usually benign, but about 1 in 10 are cancerous. A similar disease starting in the peritoneum is called solitary fibrous tumor of the peritoneum.

These benign tumors are typically removed by surgery, and there is usually no need for additional treatment.

You can read another article :
Malignant mesothelioma
Mesothelioma