basal cell carcinoma
the most common form of skin cancer, consisting of an epithelial tumor of the skin originating from neoplastic differentiation of basal cells; many patients have histories of exposure to ionizing radiation, and less often of arsenic poisoning. These skin cancers are much more common in light-skinned individuals than in the darker-skinned, and in older than younger persons; they are rarely metastatic but usually locally invasive and aggressive. Several subtypes have been distinguished; the most common type is nodular, and other types include cystic, infiltrating, morpheaform, pigmented, and superficial.
Medical dictionary.
2011.