[Microscopic diagnosis of verrucous carcinoma].

Twelve cases of verrucous carcinoma of the orofacial region were reviewed for their clinical and pathological characteristics. Verrucous carcinoma made 3.5% of all primary epidermoid carcinoma observed during the period of investigation. The tumour occurred chiefly in older patients (from 25 to 81 years, mean age 57.5) and more often in males than in females (9 males: 3 females). The most common site of occurrence was the vermilion surface of the lower lip (seven cases). Macroscopic appearance of lesions was reported as exophytic, warty, and white. Microscopically, the thickened epithelium was well differentiated and stratification was preserved. Rete pegs of carcinoma were broad and blunt; they also appeared to "puch" into underlying tissues. Basement membrane appeared to be intact. Cells of tumours were displayed, and histologic features of the spectrum were generally associated with viral modification. The prognosis in verrucous carcinoma is very good, because of the absence of metastases. Radiotherapy should not be used, since not only local recurrence is common, but also anaplastic changes may occur with corresponding aggressive behaviour and metastasis.