Verrucous Carcinoma of the Oral Cavity: A Histopathologic Study of 10 Japanese Cases

To reports ten Japanese surgical cases of verrucous carcinoma (VC) of the oral cavity.The author reviewed histopathology of 10 cases of oral VC.Ten cases of oral VC were found in our pathology department in the last 10 years. During the 10 years, a total of 187 cases of oral malignancy were recognized. Therefore, the frequency of VC was 5.3% of all oral malignancies. The patients consisted of six women and four men. The age ranged from 52 to 84 years with a median of 68 years. The locations of VC were buccal mucosa in two cases, gingiva in three cases, hard palate in one case, tongue in three cases, and soft palate in one case. The presenting symptoms were oral discomfort in two cases and tumors in eight cases. All cases underwent surgical resection. Frozen sections were performed in three cases for margin check. Grossly, all cases showed verrucous lesions. The size ranged from 0.8 to 3.2 cm with a median of 1.3 cm. Histologically, tumor cells proliferated with verrucous or papillary features. The tumor cells had acidophilic, ample cytoplasm, and nuclear atypia was minimal. Individual keratinization, koilocytosis, basal cell mild atypia, and squamous pearl formation were recognized in all cases. Three cases showed microinvasion. One case had focal ordinary squamous cell carcinoma within the VC. Epithelial dysplasia in the mucosa was recognized in the vicinity of VC in two cases. One case showed multiple tumors of VC; the number was five. Lymphocytic infiltration in the dermis was recognized in seven cases. Immunohistochemically, p53 protein was positive in all the ten cases. Its location was accentuated near the basal cells and microinvasive parts. Ki-67 positive cells were also seen mainly in the basal cells and in the microinvasive areas, and the KI-67 labeling index ranged from 12 to 21%. Two patients recurred, and additional operations were performed. None show metastatic lesions. One patient died of other disease, and nine patients are now alive without tumors.Clinicopathologic features of ten cases of oral VC were described.