No pigmented nevus

No pigmented nevus (Amelanotic nevus) : in this diseasebabyBirth or shortly after birth, along with the age growth is proportional to expand, damage often along the nerve segments, characterized by limited or extensive hair sex decrease spots, the rash is very irregular, no pigment, not as obvious as vitiligo.Sometimes white spot in mixed with hazel millet to lentils freckle spots, feel normal, such as repression surrounding skin ischemia, the diseased part and the surrounding skin line still exist.Her lesions lifelong continuously, is one of the nerve mole types.

Vitiligo and no pigmented nevus

No pigmented nevus is also called the decoloring nevus is a common birthmarks.The incidence of neonatal is about 1/125.

【 etiology pathology 】

May be is caused by somatic mutation in the early embryonic development.

"Clinical"

White spot at birth that already exist, can occur in any part of the body, but with hindquarters cadres, the most common often unilateral distribution, assumes the circular or square 0.5 ~ 10 cm size, are distributed in a few cases of segmental or systemic.

【 histopathologic 】

Damage the normal or reduce the number of melanocyte, the branches of the DCS dysplasia, melanin of melanosomes size is normal, but reducing the number.Melanin cells contain autophagy.Melanosomes gathered into a bundle.

"Identify key points"

1. Vitiligo is acquired diseases, the onset of late, and no pigmented nevus disease earlier.

2. Vitiligo border and clear, the boundary has deepened, pigment without pigment nevus, boundary is not obvious, without pigment.White spot for life unchanged.

3. Vitiligo melanocyte to reduce or disappear, no pigment nevus more normal and reduced Numbers of melanosomes, containing autophagy, melanosomes gathered into a bundle.

parting

No pigmented nevus according to lesion distribution can be divided into three type.

1) isolated type: for a single coating, round or ovoid.

(2) segmental type: skin by skin section distribution, involving one or more skin section, or along the Blaschko line distribution.

(3) type system: for involvement of the white spot, the unilateral limb white spot shape strange, turning whirlpool, stripes, similar to splatter of white paint.

Pathological changes

A base layer melanin cell count is normal, but weakened Dopa reaction,

B in silver stain within the epidermis melanin particles decreases,

C ultrastructure: melanocyte atrophy, DCS, normal or reduce the number of melanosomes.