Sections show variably keratinized stratified squamous mucosa with irregular acanthosis and focal surface hyperkeratosis. The rete ridges are often irregularly elongated and “saw-toothed.” The basal cell layer exhibits hydropic (vacuolar) degeneration with frequent scattered apoptotic keratinocytes (Civatte/colloid bodies) within the basal layer and immediate superficial lamina propria. A dense, band-like infiltrate of predominantly mature lymphocytes lies immediately subjacent to the epithelial-connective tissue interface, tightly apposed to the basement membrane. The basement membrane is focally thickened with focal fragmentation. Melanin incontinence and superficial stromal fibrosis are notes. Mitotic activity is confined to the basal layer and there is no significant upward migration of mitoses. Features of epithelial dysplasia are absent. No evidence of malignancy.
Buccal mucosa white stria.
Soft tissue fragment measured 0.5x0.4x0.3 cm, totally embedded.
Buccal mucosa lesion, excision biopsy: