Verrucous hyperplasia of the oral mucosa.

Verrucous hyperplasia of the oral mucosa is a relatively unrecognized entity that may resemble verrucous carcinoma clinically and histologically. This study describes the clinical and histological features of the condition, particularly in relation to verrucous carcinoma. Sixty-eight cases were selected by screening all lesions accessioned as verrucous or papillary lesions of various kinds, dysplasias and leukoplakias. More cases occurred in women (56%) than in men (44%). All but 3 patients were 50 yr. or older, and 35% were over 70. Gingiva or alveolar mucosa were involved most frequently (27%), followed by cheek (24%), tongue (17%), floor of mouth and lip (12% each), and palate (8%). Verrucous processes are either sharp and heavily keratinized or blunt with a thin parakeratin layer. In 36 patients (53%), there was associated leukoplakia; in 20 (29%), there was associated verrucous carcinoma; in 45 (66%), associated epithelial dysplasia; and in 7, (10%) there was associated squamous carcinoma. Verrucous carcinoma or squamous carcinoma. Verrucous hyperplasia is best distinguished from verrucous carcinoma in biopsies taken at the margins of the lesions. In the former, the verrucous processes and the greater part of the hyperplastic epithelium are superficial to adjacent normal epithelium. In the latter, the verrucous processes are superficial, but the broad rete processes extend considerably deeper than adjacent normal epithelium, often pulling a margin of normal epithelium down with them into the underlying connective tissue.