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Skin-Melanocytic tumors / Clinical Dermatology
Other melanocytic lesions
Vitiligo
Reviewer: Mowafak Hamodat, MB.CH.B, MSc., FRCPC, Eastern Health, St. Johns, Canada (see Reviewers
page)
Revised: 1 August 2011, last major update August 2011
Copyright: (c) 2002-2011, PathologyOutlines.com, Inc.
Definition
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● Partial or complete loss of pigment producing melanocytes within the epidermis
Epidemiology
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● Affects 1% of world’s population; more noticeable in dark skinned individuals
● Usually hands/wrists, axilla, perioral, periorbital, anogenital skin
Clinical features
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● Autoimmune disorder associated with pernicious anemia, Addison’s disease, Hashimoto’s thyroiditis
● Perilesional skin up to 5 cm from vitiligo spot is still lighter than normal (Photodermatol Photoimmunol Photomed 2008;24:314)
● Associated with polymorphisms in COX2 gene (J Dermatol Sci 2009;53:176), mutations of autoimmune regulator gene
(Br J Dermatol 2008;159:591)
● May cause severe psychological distress
Patterns
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● Focal: only a few areas
● Segmented: one side of the body only
● Generalized: most common, both sides of body
● Trichrome: patient has three shades of skin color
Treatment and prognosis
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● Laser skin ablation; phototherapy; 5 FU (Photodermatol Photoimmunol Photomed 2008;24:322)
● Topical steroids or immunomodulators (J Dermatol 2008;35:503)
● Hydroxyacetone (Dermatol Online J 2008;14:23)
Clinical description
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● Asymptomatic, flat, well-demarcated zones of pigment loss
Clinical images
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Various images
Micro description
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● Difficult to diagnose by histology; decreased melanocytes (use S100 or MelanA and control biopsy from adjacent normal skin, Am J Dermatopathol 2008;30:112)
● At advancing border, melanocytes may be increased in size with an increased number of dendrites; occasionally lymphocytes are present in this region, particularly if an inflammatory border is present; epidermotropic lymphocytes may form small Pautrier-like collections in the basal layer, with an associated perivascular infiltrate of mononuclear cells involving the superficial plexus and some superficial edema
● Focal spongiosis may be present in marginal areas
● Degenerative changes have also been reported in nerves and sweat glands
● Langerhans cells are usually increased
● Melanocytes are always reduced more in vitiligo than they are in nevus depigmentosus
EM description
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● No melanocytes
Differential diagnosis
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● Albinism: melanocytes are present, but no melanin due to defect in tyrosinase enzyme
Additional references
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End of Skin-Melanocytic tumors / Clinical Dermatology > Other melanocytic lesions > Vitiligo
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