Be vigilant for skin manifestations of inherited cancer syndromes.

More than 200 hereditary cancer susceptibility syndromes have been described, and it is thought that they account for 5-10% of all cancers. Many have dermatological manifestations (usually lesions, occasionally rashes) which frequently precede other systemic pathology. Dermatological signs are usually non-specific and often trivial in appearance, making their significance easy to overlook and a clinical diagnosis challenging. Histological examination is often required to differentiate lesions. They are usually benign and pathologically unrelated to the primary tumours, with the exception of the atypical moles of the dysplastic naevus syndrome, and may present simply as a cosmetic problem for the patient. However, a number of cancer syndromes exhibit an increased risk of developing malignant skin lesions. For instance, Gorlin syndrome (nevoid basal cell carcinoma syndrome) which typically results in the development of multiple basal cell carcinomas, within the first few decades of life. The majority of cancer syndromes with skin signs are inherited in an autosomal dominant pattern demonstrating complete penetrance before the age of 70. Once a cancer syndrome has been diagnosed, the cornerstone of management is frequent surveillance for the early detection and treatment of malignancy. Genetic testing and counselling should be offered to family members.