Histology of benign virus induced tumors of the skin.

The majority of findings in relation to warts have been passed on from one textbook to the other since the end of the last century. More recent studies have been carried out with the electron microscope. But information is lacking as to histology, histochemistry, examination with the phase-contrast microscope, with the interference microscope, microradiography and other new techniques. Warts are a proliferation of the epidermis caused by a virus, and we know that the culprit acts in the epidermis itself. Warts are acanthomas, and a transition to malignancy is possible in predisposed persons. It is most remarkable that in the malignant tumors of epidermodysplasia verruciformis, no virus could be found. As the demonstration of viruses with the electron microscope and other techniques cannot be made as a matter of routine, we have to search for a simpler method with the light microscope. With the application of more elaborate procedures, new information about epidermal proliferation will certainly be obtained.