Factors Predisposing to Pseudocarcinomatous Hyperplasia and to Malignant Transformation of the Epidermis

Abstract

This considers factors, both endogenous and exogenous, which are conducive to pseudocarcinomatous hyperplasia of the epidermis and which may also have a role to play in its premalignant and malignant transformation. While some of these factors are carcinogenic in the broad sense, they may evoke either reactive or precancerous epidermal hyperplasia depending on the duration of exposure to them and on the state of the body. For example, a single trauma may result in the formation of a trophic ulcer and promote the development of ulcerative pyoderma, in both of which conditions pseudocarcinomatous epidermal hyperplasia is often seen to arise, whereas exposure of a skin area to repetitive trauma may lead to premalignant changes; or, inappropriate topical application of drugs in certain dermatoses (lichen ruber verrucosus, psoriasis, lupus erythematosus, etc.) may bring about either changes that clinically stimulate malignant transformation or a true squamous cell carcinoma of the skin.