There are different types of mesothelioma. They may be categorized by either location or cells.
By location: There are four types of mesothelioma. Each type affects the mesothelium, a lining around most of your internal organs that is formed by mesothelial cells. The role of the mesothelium is to protect what it surrounds, keeping it in place and allowing for movement without friction. Benign or malignant tumors develop when mesothelial cells start to multiply out of control. The type of mesothelioma you have is determined by the location of the affected mesothelium.
By cells: Mesothelioma may be separated into three types when looking at the cellular makeup of cancerous tissue under a microscope (histology and histopathology).
This is predominately made up of epithelial cells (most common and usually the most responsive to treatment). Deciduoid is a sub-type.
This is predominately made up of sarcomatoid cells (least common and usually the most difficult to treat). Desmoplastic, lymphohitiocytoid and small cell are sub-types.