The pathologic diagnosis of diffuse PM should include compulsory points based on different drug approvals in different European countries and according to the last fifth edition of the WHO [4] classification of pleural tumors, such as the nuclear grade of the epithelioid-type mesothelioma, the presence of BAP1 (clone C4) protein loss, and a statement on the presence of the sarcomatoid/nonepithelioid component. Here, BAP1 is linked to mesothelioma.