GIANT DESMOSOMES IN TUMORS

The lengths of desmosomal profiles were measured in sections of tumor tissue from cases of mesothelioma, adenocarcinoma, squamous cell carci noma, thymoma, and meningioma. Giant desmosomes (length of profile 1 m u m or greater than 1 mu m) were found in all the above-mentioned tumo rs except adenocarcinomas. The largest desmosomal profile in adenocarc inoma was similar to 0.8 mu m long; the largest in mesothelioma was si milar to 2 mu m long. Our observations suggest that one of the ways in which giant demosomes arise is by growth and fusion of adjacent desmo somes. Giant desmosomes may at times help in distinguishing mesothelio ma from adenocarcinoma, but this is a rather rare phenomenon. In this study giant desmosomes were found in only 2 out of 10 cases of mesothe lioma.