|Year : 2016 | Volume
| Issue : 1 | Page : 67-69
Vitiligo developing within congenital melanocytic nevus
Damarla Sudha Vani, Arakkal Geeta Kiran, Chintagunta Sudha Rani, Siddavaram Divya
Department of DVL, Gandhi Medical College, Hyderabad, Andhra Pradesh, India
|Date of Web Publication||18-Mar-2016|
Damarla Sudha Vani
Department of DVL, Gandhi Medical College, Hyderabad, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Development of vitiligo or halo naevus within or around congenital melanocytic naevus (CMN) is a rare phenomenon. Very few cases on regression of CMN after the onset of halo naevus or vitiligo were reported in the literature. We hereby report a case of 25 yr old female who presented with giant CMN since birth and development of vitiligo lesions within the CMN for the past 5yrs which is gradually progressing and showing regression of CMN.
Keywords: Congenital melanocytic nevus, vitiligo, regression
|How to cite this article:|
Vani DS, Kiran AG, Rani CS, Divya S. Vitiligo developing within congenital melanocytic nevus
. J NTR Univ Health Sci 2016;5:67-9
| Introduction|| |
Congenital melanocytic nevi (CMN) occur in 0.6-1.6% of newborn.  They are divided into small (<1.5 cm), medium (1.5-10 cm), large (11-20 cm) and giant CMN (>20 cm). Giant CNM is a rare condition with an incidence of one in twenty thousand births, ,, but vitiligo developing within giant CMN is very rare.
Vitiligo is an acquired disease with a genetic predisposition characterized by the progressive depigmentation of the skin which affects 0.5-2% of the general population.  Autoimmune, catatonic and neural hypothesis were proposed to explain the etiology of vitiligo. Vitiligo may be associated with other autoimmune diseases. The presence of melanocytic antibodies and lymphocytic infiltrates in vitiligo indicates probable autoimmune etiology, which is a widely accepted hypothesis.  Vitiligo can occur as vitiligo vulgaris, segmental vitiligo or vitiligo acrofacialis.
We describe a patient with CMN, who presented with depigmented patches within the nevus, followed by development of similar patches in areas other than the primary lesion.
| Case report|| |
A 25-year-old female patient presented with a giant melanocytic nevus with coarse hair since birth involving the left buttock, thigh and extending up to the knee [Figure 1] and [Figure 2]. Multiple, discrete CMN of varied sizes ranging from 1 cm to 25 cm were present over the upper limb, trunk and lower limbs [Figure 3]. She developed large depigmented patch within the giant CMN over the thigh that is gradually progressing for the last 5 years. Depigmented patches were also seen over the eyelid and left flank. There was no evidence of other associated autoimmune disorders or melanoma. A detailed clinical examination and laboratory investigations including computed tomography of the brain revealed no abnormalities. HPE of the lesion showed nervous cells in the dermis that expressed S100 protein on immunohistochemistry and loss of melanocytes in the epidermis [Figure 4] [Figure 5] [Figure 6].
|Figure 1: Giant melanocytic nevus with hypertrichosis and depigmented patches within the nevus on the left thigh|
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|Figure 2: Giant melanocytic nevus with hypertrichosis and depigmented patches within the nevus on the left thigh (posterior aspect)|
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|Figure 5: Nevus with vitiligo focus, nevoid cells within the dermal tissue|
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|Figure 6: Epidermis showing transition of loss of melanocytes, dermis showing nevus cells|
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| Discussion|| |
The association of CMN and vitiligo is a rare co-existence. The evolution of CMN with vitiligo varies widely. The spectrum of prognosis ranges from remaining unaltered throughout life to undergoing malignant degeneration or sometimes showing spontaneous regression.
Incidence of CMN is 0.6-1.6% in newborns.  They are classified based on their size. There is remote chance of developing malignancy in CMN lesions with the risk being less in small and medium sized CMN and high in the large and giant CMN, the risk ranges from 1% to 42%. The risk of developing malignancy in giant CMN is more before puberty whereas it is higher in small and medium sized nevi after puberty.  A depigmentation can develop around or inside the nevus. Itin and Lautinschlage  reported depigmentation of CMN and a white colored halo around the nevus in a 6-year-old boy. Halo around the nevus developed when he was 3 years old with depigmented lesions occurring 1 year later. Recently Dainich et al.  reported a case where CMN disappeared after the concomitant onset of the vitiligo vulgaris at the age of 19 years with the disappearance of almost all nevus cells from a lesion of CMN. In contrast our patient showed features of spontaneous regression of the nevus, indicating the pathogenic mechanism of vitiligo, probably involving the melanocyte specific cytotoxic T-cells which attack not only epidermal and follicular melanocytes but also nevus cells.
A giant CMN per se carries a considerable risk of malignant transformation. 
The simultaneous appearance of CMN and vitiligo and presence of cytotoxic CD8 positive T-cells in both lesions suggest a common immunological mechanism developed against similar molecular targets. It is difficult to predict the evolution of CMN because it could regress without developing a vitiligo  or halo nevus  or in contrast could remain stable and even exhibit repigmentation in the halo nevus. Hence, CMN must be followed for life, particularly in the case of giant nevi, where risk of melanoma is very high. An association between vitiligo and melanoma has been found providing an additional reason for follow-up of CMN.
The phenomenon of regression of the CMN with enlarging vitiligo lesion within the CMN and elsewhere on the body is seen in our case.
In view of the multiple small and medium melanocytic nevi over the trunk and limbs in addition to giant melanocytic nevus, our patient requires close observation for the development of melanoma at a later stage.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]