[Creole dyschromia or idiopathic macular hypomelanosis of the melanodermic halfcast of Guillet-Hélénon].

Melanodermic halfcasts may develop an original cutaneous dyschromia known as "progressive and extensive hypomelanosis" (Guillet-Helenon 1988). This disease is characterized by hypochromic and coalescent macules on the back and abdomen with possible spontaneous improvement within five years, favoured by UV exposure. The disease is not restricted to a limited geographic group: eight observations were collected in melanodermic patients leaving in temperate area. The pathogenesis of the disorder involves a variation in melanosome size and distribution with decrease in production of type IV melanosomes featuring a change of ultrastructural phenotype of melanogenesis. Since it may be misdiagnosed as fungal disease, leprosy or achromic eczema leading to useless laboratory examinations, this specific and frequent disease deserves to be known and recognized.