This chapter covers the four most common hamartoneoplastic syndromes, including neurofibromatosis type 1, tuberous sclerosis, Gardner syndrome and Cowden syndrome. These conditions have diverse clinical and genetic features and require detailed condition‐specific knowledge, along with specific treatment guidelines and plans. They are, however, united by the common features of extensive and diverse skin manifestations along with somatic hamartomas and a significant risk of cutaneous and non‐cutaneous neoplasia. The four conditions are reviewed in detail with respect to pathophysiology, clinical features, diagnosis and management. A brief review of the emerging field of disorders with the collective term ‘RASopathies’ is included.
Keywords hamartoma, tumour suppressor gene, tuberous sclerosis, neurofibromatosis, Gardner syndrome, Cowden syndrome