Aspects of heredity, syndromic associations, and course of conditions in which cutaneous lesions occur solitarily or in multiplicity.

Many tumors of the skin, whether originating from ectoderm or mesoderm, exist in either single or multiple form. In the multiple state there are frequently associations with other cutaneous and systemic abnormalities, sometimes serious and even life-threatening. The resultant syndrome is almost always inherited in an autosomal dominant pattern. By contrast, solitary lesions are not heritable, nor are they associated with other stigmata. The solitary forms appear in middle or late life, the multiple, syndromic forms in childhood or early adulthood.