Oral squamous cell carcinoma (SCC) of the buccal mucosa is described histologically. From which epithelial layer does this malignancy originate?

Squamous cell carcinoma (SCC) arises from the squamous cells of the stratum spinosum (prickle cell layer) of stratified squamous epithelium. The keratinocytes in the stratum spinosum are the predominant cell type that undergoes malignant transformation in SCC. These cells are characterized by their intercellular desmosomes (prickles). In contrast, basal cell carcinoma (BCC) — which occurs in the skin but not the oral mucosa — arises from the stratum basale. The stratum corneum contains anucleate, dead keratinocytes with no proliferative capacity. The stratum granulosum contains keratohyalin granules and is a transitional layer.