Fig. 4

a–d Atypical epithelial cells (arrows) of different shapes in fibromycoidic stroma with trabecular structures (a) × 20 and (b); atypical epithelial cells with eosinophilic cytoplasm and insignificant polymorphic oval nuclei (c) × 20; tumor gingival mucosa with normal structure of stratified squamous cell epithelium (d) × 10 (haematoxylin and eosin staining)