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Nevus anemicus
Nevus anemicus
Clinical features Nevus anemicus is a congenital anomaly characterized by an asymptomatic, ill-defined patch of slightly hypopigmented skin with predilection for the
1000 Disorders of pigmentation
Pathogenesis and histologic features The etiology of nevus depigmentosus is as yet unknown but in cases with a systematized distribution it has been suggested that the lesion is the result of a somatic mutation.7
Histology has been reported as showing a normal or reduced number of melanocytes.3 More recently, however, it has been suggested that there is decreased pigmentation but a normal number of melanocytes.3 Electron microscopy studies suggest that there may be a defect in the transfer of melanosomes, and aggregates of melanosomes have been observed in keratinocytes.3,6
Fig. 20.19 Nevus depigmentosus: segmental distribution. By courtesy of the Institute of Dermatology, London, UK.