Pathological recognition of diffuse malignant mesothelioma of the pleura: the significance of the historical perspective as regards this signal tumor.

Diffuse malignant mesothelioma (DMM) is a distinctive tumor which provides an uncommon opportunity to observe the gradual appreciation and increasing incidence of a new disease. DMM is a new disease. One cannot comment intelligently about the pathology of sporadic cases that might have occurred before the beginnings of anatomic pathology, but we do know that there were so few cases before 1930 that the very existence of the disease was not accepted in general before 1930 and not accepted by all pathologists even up until 1960. Because DMM is increasing on a worldwide basis and is making its appearance in the developing world, where it has not previously been diagnosed, appreciation of how the disease came to be noticed sheds light on its causation. As a signal tumor for exposure to asbestos, and knowing that all special exposures contribute to the development of the disease, knowledge of its continuing escalation underscores the importance of recognition of previously unimplicated or occult exposures for reasons of public health in both developed and developing countries.