FAMILIAL LINEAR AND WHORLED NEVOID HYPERMELANOSIS

Two patients with familial linear and whorled nevoid hypermelanosis, a 33-year-old woman and her 3-month-old daughter, are described. These are the first cases of linear and whorled nevoid hypermelanosis of fam ilial occurrence reported in the literature. Asymptomatic hyperpigment ed macules in streaky configurations had appeared on the trunk and ext remities of both patients several weeks after birth and then gradually spread. No previous inflammation or eruption was observed. Histologic examination revealed a slight increase in the number of melanocytes i n the epidermis and an irregular basal melanosis. No pigmentary incont inence or melanophages were observed in the dermis. Ultrastructurally the only finding was an increase in the number of normal-appearing mat ure melanosomes in keratinocytes in the lesion. Chromosomal analysis o f cultured peripheral blood lymphocytes and dermal fibroblasts from no rmal and pigmented skin revealed no evidence of mixoploidy or chimeris m. An undescribed genetic abnormality is suggested as the cause.