Morphological features of epithelial abnormalities and precancerous lesions of the penis.

There is a heterogenous spectrum of abnormalities and atypical lesions in the penile epithelium. The terminology used to designate precursor lesions is variable but squamous intraepithelial lesions of low and high grade or penile intraepithelial neoplasia I, II and III are the recommended terms. Other probable precursor lesions are squamous hyperplasia and bowenoid papulosis. Low- and high-grade squamous intraepithelial lesions may be classified into squamous or simplex, the most frequent types, or warty (condylomatous) and basaloid. There is a striking morphological correspondence between precancerous lesions of the penis and their respective invasive lesions. The presence of two groups of lesions in the precancerous as well as invasive carcinomas, the squamous typical and the warty basaloid, is consistent with the bimodal hypothesis of the existence of non-HPV (the typical squamous) and HPV-related (warty or basaloid) tumors.