Malignant mesothelioma is a rare aggressive malignancy of serosal surfaces that is strongly associated with exposure to asbestos. The pathological diagnosis of malignant mesothelioma can be difficult to distinguish from reactive benign hyperplasia. Mutations in BAP-1 and CDKN2a distinguish mesothelioma from reactive hyperplasia. An in situ growth phase of mesothelioma until recently was difficult to ascertain due to limits of histological assessment and because mesothelioma tends to spread diffusely along serosal surfaces making sampling for invasion impossible without extensive resection. The current WHO classification of thoracic tumors recognizes mesothelioma in situ as a distinct entity based on histological, genetic, and clinical features. This chapter reviews the topic and concludes that the diagnosis of malignant mesothelioma in situ should be limited to patients eligible for radical resection to confirm the putative diagnosis.
Part of the book: Rare Diseases
Malignant mesothelioma is a rare malignancy of serosal-lined tissues. It has been recognized since the last century that the majority of pleural mesotheliomas are caused by exposures to asbestos, a fibrous silicate mineral that was used extensively in the construction trades for its insulating properties. A previously unrecognized source of asbestos exposure is cosmetic talc that has been widely used for personal hygiene and other purposes by adults and children. Since 2014, more than 200 cases of mesothelioma have been reported in individuals, whose only known source of asbestos exposure was cosmetic talc. In this chapter the association of talc with malignant mesothelioma will be reviewed.
Part of the book: Challenges in Pleural Pathology