Giant desmosomes in tumors.

The lengths of desmosomal profiles were measured in sections of tumor tissue from cases of mesothelioma, adenocarcinoma, squamous cell carcinoma, thymoma, and meningioma. Giant desmosomes (length of profile 1 micron or greater than 1 micron) were found in all the above-mentioned tumors except adenocarcinomas. The largest desmosomal profile in adenocarcinoma was approximately 0.8 micron long; the largest in mesothelioma was approximately 2 microns long. Our observations suggest that one of the ways in which giant desmosomes arise is by growth and fusion of adjacent desmosomes. Giant desmosomes may at times help in distinguishing mesothelioma from adenocarcinoma, but this is a rather rare phenomenon. In this study giant desmosomes were found in only 2 out of 10 cases of mesothelioma.