Verrucous carcinoma of skin: epithelioma cuniculatum plantare.

Eight patients had plantar growths that were usually irregularly shaped, sharply outlined, verrucous, and several centimeters in greatest dimension. Clinical diagnoses included viral wart, deep mycosis, pyogenic granuloma, amelanotic melanoma, basal cell carcinoma, and eccrine poroma. The median age of the patients, and duration of the growth, were 52 and 16 years, respectively. Therapeutic modalities other than total excision were ineffective. The tumor, derived from surface epidermis, was composed of masses of pale-staining benign-appearing prickle cells, deeply invaginated by thick, compact, partially parakeratotic horn. Several lesions have recurred; amputation was required in one patient. This distinctive entity, apparently not described in the American literature, has been reported from Europe under such titles as epithelioma cuniculatum and papillomatosis cutis carcinoides. We believe that it is best interpreted as a form of verrucous carcinoma, the first cutaneous tumor--as opposed to lesions of mucous membranes and mucocutaneous junctions--to be so classified.