Guidelines for pathologic diagnosis of malignant mesothelioma: 2012 update of the consensus statement from the International Mesothelioma Interest Group.

TLDR: These guidelines are meant to be a practical reference for the pathologist and recommend that immunohistochemical markers have either sensitivity or specificity greater than 80% for the lesions in question.

Abstract: Context.—Malignant mesothelioma (MM) is an uncommon tumor that can be difficult to diagnose. Objective.—To provide updated practical guidelines for the pathologic diagnosis of MM. Data Sources.—Pathologists involved in the International Mesothelioma Interest Group and others with an interest in the field contributed to this update. Reference material includes peer-reviewed publications and textbooks. Conclusions.—There was consensus opinion regarding (1) distinction of benign from malignant mesothelial proliferations (both epithelioid and spindle cell lesions), (2) cytologic diagnosis of MM, (3) key histologic features of pleural and peritoneal MM, (4) use of histochemical and immunohistochemical stains in the diagnosis and differential diagnosis of MM, (5) differentiation of epithelioid MM from various carcinomas (lung, breast, ovarian, and colonic adenocarcinomas, and squamous cell and renal cell carcinomas), (6) diagnosis of sarcomatoid mesothelioma, (7) use of molecular markers in the diagnosis of MM,...