The cells of a basal cell carcinoma are dark blue and oblong with scant cytoplasm. They resemble the cells along the basal layer of normal epidermis. The cells are arranged into nests or trabeculae that infiltrate down into the dermis. The typical nest has a pallisaded arrangement of cells around the periphery. The nests have an intervening fibrous stroma with variable inflammatory cell component. The overlying epidermis can ulcerate. Some variants have squamous metaplasia and keratinization, making them difficult to differentiate from squamous cell carcinoma.

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