title: On the nature of idiopathic guttate hypomelanosis.
abstract: Clinical and morphologic studies were made of 20 cases of guttate hypomelanosis. The sharply demarcated hypopigmented macules were present on both covered and exposed sites, excluding sunlight exposure as a cause. Skin surface replicas and biopsies showed no evidence of post-traumatic or post-inflammatory scarring. The stratum corneum had fewer cell layers, but no abnormalities of keratinization were observed. Light and electron-microscopic and histochemical studies showed only reduced numbers of hypoactive melanocytes. In no case were melanocytes completely absent, excluding vitiligo. Guttate hypomelanosis is a common disorder of unknown origin. The evidence indicates an age-related somatic mutation of melanocytes.
mesh_terms: D000367:Age Factors; D000368:Aged; D001706:Biopsy; D044383:Black People; D005260:Female; D006801:Humans; D008297:Male; D008544:Melanocytes / Q000648:ultrastructure; D008875:Middle Aged; D010859:Pigmentation Disorders / Q000453:epidemiology / Q000209:etiology / Q000473:pathology*; D012867:Skin / Q000473:pathology / Q000648:ultrastructure; D013472:Sunlight