pleural plaque

A pleural plaque is like a callus on the lining of the chest: a discrete patch of thickened, fibrous tissue, often hard and calcified, sitting on the pleura. By itself it is a scar, not a tumor — a quiet marker that the pleura was once exposed to an irritant, most famously asbestos.

Plaques typically form on the pleura lining the chest wall and over the diaphragm, usually on both sides, decades after asbestos exposure. They are commonly found by chance on a chest film or CT done for some other reason. The great majority are benign, cause no symptoms and do not impair breathing, and they do not themselves turn into cancer.

Their importance is mostly as a signpost. A plaque confirms past asbestos exposure, which matters because that same exposure carries a separate, increased risk of more serious asbestos-related disease such as mesothelioma or lung cancer. So a plaque is reassuring in itself but is a reason to keep the bigger picture — and the exposure history — in mind.