LUNG - Hydatid disease

The cut surface of the specimen, which consists of the whole of one lung, shows at least six cysts, up to 8 cm. in diameter. Two of the cysts show thin, almost translucent membrane and, in the upper cyst, the membrane has become detached and lies below the cyst. The cyst walls are of varying thickness; the wall represents the host's reaction to the parasite, and is called the pericyst. The outer surface of the lung shows marked pleural thickening, and the fat that can be seen indicates that, at these points, the pleural surfaces were firmly adherent. The outer surface of the lung also shows a number of cysts, which have been opened for display.