Basal cell carcinoma (BCC) represents the most common skin malignancy, which has been linked over time to multifactorial causes. It usually occurs on sun-exposed areas in people with fair skin and with predilection for men. BCC usually affects elderly patients and has an extremely wide range of histological subtypes, which can present clinically under different variants, some with really challenging differentials. Although BCC may occur in familial settings, such as nevoid BCC syndrome, Rombo or Bazex–Dupré–Christol syndromes, nonsyndromic multiple BCCs have also been described in the scientific literature. In this review, we discuss in detail the latest scientific concepts regarding BCC, its etiology, pathogenesis, genetic bases of disease, morphology and immunophenotype, as well as the currently known genetic syndromes, which may lead to development of multiple BCCs, especially in young adults.