Congenital and genetic disorders of hyperpigmentation

Abstract

Pigmented skin lesions are often the initial clue to the presence of an underlying disorder or syndrome. In evaluating such conditions, it is helpful to categorize the lesions according to their morphology and distribution. A diagnostic approach is provided, with the general topics consisting of melanocytic nevi, widespread or localized “spotty” pigmentation such as simple lentigines, cafe-au-lait macules, hyper-pigmentation along the lines of Blaschko, reticulate pigmentation, dermal melanocytosis, dyschromatosis, and other unique pigmentary patterns. Within this framework, we outline and review a variety of congenital and genetic disorders of hyperpigmentation, including giant congenital nevi and neurocutaneous melanosis, the multiple lentigines syndrome, Carney syndrome, and Peutz-Jehgers sywdrome, the neurofibromatoses, the McCune-Albright syndrome, incontinentia pigmenti and other conditions due to genetic mosaicism, dyskeratosis congenita and Fanconi's anemia, nevus of Ota, and many other conditions in which cutaneous pigmentation signals an underlying disorder. Diagnostic criteria and suggested clinical evaluation are provided when applicable.