Clinical Features and Histopathological Characteristics of Nevus Depigmentosus

Lee, Han Seung; Kim, Soo Min; Hann, Seung Kyung

Abstract

BACKGROUND: Nevus depigmentosus was first reported in 1884 by Lesser. It is defined as a congenital non-progressive hypopigmented macule or patch that is stable in its relative size and distribution throughout the life of the individual. The etiopathogenesis and histopathological characteristics of nevus depigmentosus are not fully established. OBJECT: The purpose of this study is to investigate the clinical and histopathological characteristics and pathogenesis of nevus depigmentosus.
METHODS
Clinieal survey was carried out on forty-nine patients with nevus depigmentosus and two skin biopsies were taken from eighteen patients; from the central part of the depigmented lesion and the border of the lesion including the perilesional normal skin. The sections were stained with hematoxylin-eosin, Fontana-Masson and S-100 protein. The ultrastructural evaluation were also done to detect alternation of melanocytes.
RESULTS
The results are as follows ; 1. The lesions were mostly (91.8%) present before the age of three, but some lesions appeared in childhood (8.2%). 2. The lesions were most frequently found on the trunk (42.9%), followed by the face and scalp (20.4%). 3. There were 33 patients (67.3%) with the isolated type, 15 patients (30.6%) with the dermatomal type and one patient with the whorled type. 4. Histopathological studies have shown that the stainability of Fontana-Masson in the lesions of nevus depigmentosus was decreased compared with perilesional nomal skin, but there were no changes in the number of melanocytes. 5. There was a great reduction in the number of melanosomes in melanocytes and keratinocytes of nevus depigmentosus. In keratinocytes, there was some aggregations of melanosomes and some of them showed membrane bound architecture.
CONCLUSION
The results of this study support the fact that nevus depigmentosus is caused by functional defects of melanocytes and morphological abnonnalities of melanosomes.