Multiple verrucous carcinomas of the oral cavity

The author herein reports a case of multiple verrucous carcinomas (VCs) of the left lower gingiva. A 78-year-old man was admitted to our hospital because of gingival tumor. A biopsy revealed severe dysplasia. Surgical resection was performed. Grossly, there were three verrucous lesions (25, 20, 10 mm) in the left lower gingiva. Histologically, 2 tumors (4, 2 mm) were found in addition to the grossly visible 3 tumors. All the 5 tumors were VCs. The tumors showed verrucous and papillary proliferation of squamous epithelium with little cellular atypia. No invasive features were recognized. The dermis showed lymphocytic infiltration. The surrounding mucosa showed many broad foci of squamous cell carcinoma in situ and severe dysplasia (high grade intraepithelial neoplasm). Gradual merges between the VCs and squamous cell carcinoma in situ or severe dysplasia were frequently recognized. Immunohistochemically, the VC tumor cells and squamous lesions were negative for human papilloma virus antigens. P53 protein was expressed in all the VCs and squamous epithelial lesions: it was accentuated in the basal and suprabasal cells of VC. Ki-67 antigen was also expressed in the 5 VCs and in the squamous lesion, and Ki-67 labeling index ranged from 8 to 16 % in VC and from 37 to 62 % in the squamous lesions. These data support the multicentric nature of VC and that the severe dysplasia-carcinoma in situ sequence have been proposed in the etiology of VC.