[Segmental pigment anomaly with neurologic disorders].

A 28-year-old female patient who developed an asymmetrically localized depigmentation on the right arm and on the right side of the trunk shortly after birth is presented. The depigmented areas with hyperpigmented macules within them had not changed in shape or extent since their development. At the age of 18 years, neurological alterations (hyporeflexy, sensory deficiencies, muscle atrophy and paralysis) were also observed. Ultrastructural investigations revealing the lack of melanocytes in the depigmented areas and the presence of atypical melanosomes in the hyperpigmented macules indicate a rare pigmentation disorder.