Fig. 1

Clinical and histopathological findings of the initial lesion that arose in the left buccal mucosa. A Intraoral view at the first examination: the patient presented with a tumor in the left buccal mucosa that had a granular surface and measured 22 × 19 mm. B, C Histopathological examination of the biopsy specimen revealed squamous cell carcinoma without obvious keratinization (hematoxylin and eosin staining; scale bar 200 μm [B] and 100 μm [C]). D An intraoral view after chemoradiotherapy showed that the tumor had disappeared