Clinical And Histopathologic Characteristics Of Nevus Depimentosus

PartⅠClinical characteristics of nevus depigmentosusObjectiveTo study the clinical characteristics of nevus depigmentosus.MethodsA clinical survey was carried out with 85 patients given the diagnosis of ND. We recorded and analyzed the clinical data included sex, age, age of onset, pattern of lesions, involved sites, sharp and number of lesions and associated systemic disease.ResultsThe lesions were usually present before the age of 3 years (75.3%).39 patients (45.9%) had the isolated type of nevus depigmentosus and 46 patients(54.1%) had the segmental type.The trunk was the most commonly affected site (29.4%). The margins of lesions were most irregular(84.7%).54 patients (63.5%) had one lesion. The leukodermas were relative stable in size and distribution throughout life. The mean MIs of ND lesion was 186.56±52.86 and the mean RMIs is 80±11, which was significantly decreased than normal (MIs=223.88±63.19) and higher than those of vitiligo (MIs=128.57±64.31, RMIs=60±20)ConclusionsNevus depigmentosus is an early-onset nonfamilial stable leukoderma with irregular margins. RMI is an effective parameter for increasing diagnostic accuracies in hypopigmentary disorders. PartⅡHistopathologic characteristics of nevus depigmentosusObjectiveTo investigate the histopathologic and ultrastructural characteristics of nevus depigmentosus.MethodsTwo skin biopsy specimens each were taken from 17 patients:one from the depigmented lesion and another from the perilesional normal skin. The sections were stained with haematoxylin and eosin, Fontana-Masson, antibodies to TYR, HMB45, TRP-1, TRP-2 and CD117. Observe ultrastructure of lesions with transmission electron microscopy.ResultsFontana-Masson stain and immunohistochemistry shows that the melanin content of ND lesions was significantly decreased compared with perilesional normal skin, and the number of melanocytes also decreased stained with antibodies to TYR and TRP-1. However, there were no significant differences in the number of melanocytes identified as HMB45, TRP-2 and CD117-positive cells. Ultrastructural study demonstrated that decreasing of MC and melanosomes, some aggregated melanosomes were presented in affected keratinocytes, and there were premelanosomes in MC and KC.ConclusionsBoth the content of melanin and number of MC in ND lesions were decreased. The number of Premelanosomes in MC and KC is increased than perilesional normal skin. Probably ND is associated with reduction of MC and disorder in the melanonization.PartⅢCharacteristics of ND in vivo by confocal laser-scanning microscopy ObjectiveTo study the characteristics of ND in vivo by confocal laser-scanning microscopy.MethodsObserved the lesions of ND and normal skin by confocal laser-scanning microscopy, and compare the diameter, density and brighteness of melanin in basal layer.ResultsThe number of MC and the brightness of melanin caps were decreased. They were at the dermoepidermal junction around the dermal papillae. The border of lesion and normal zone is non-clear.ConclusionThe results were according to the findings of histopathology. So CLSM is an in-vasive method to increase diagnostic accuracies in hypopigmentary disorders.