摘要: Basal cell carcinoma is the most common human cancer. Its incidence steadily increasing. The development of basal linked to genetic factors, including individual skin phototype, as well cumulative exposure UVB. vast majority carcinomas are sporadic tumors, while familial cases associated with certain hereditary syndromes less common. At molecular level, characterized by aberrant activation sonic hedgehog signaling, usually due mutations either in ptch or smoh genes. In addition, about half carry tp53 tumor suppressor gene, which often UVB-associated C-->T transition mutations. Clinically, may show a high degree phenotypical variability. particular, tumors occurring atypical locations, showing an unusual clinical appearance, imitating other diseases cause diagnostic problems. This review article summarizes current state art concerning etiology, predisposition and genetics carcinoma. examples manifestations illustrated.