Home   Chapter Home   Jobs   Conferences   Fellowships   Books



Advertisement

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
=========================================================================

● Partial or complete loss of pigment producing melanocytes within the epidermis

Epidemiology
=========================================================================

● Affects 1% of world’s population; more noticeable in dark skinned individuals
● Usually hands/wrists, axilla, perioral, periorbital, anogenital skin

Clinical features
=========================================================================

● 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
=========================================================================

● 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
=========================================================================

● 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
=========================================================================

● Asymptomatic, flat, well-demarcated zones of pigment loss

Clinical images
=========================================================================


   
Various images

Micro description
=========================================================================

● 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
=========================================================================

● No melanocytes

Differential diagnosis
=========================================================================

Albinism: melanocytes are present, but no melanin due to defect in tyrosinase enzyme

Additional references
=========================================================================

Wikipedia, eMedicine

End of Skin-Melanocytic tumors / Clinical Dermatology > Other melanocytic lesions > Vitiligo


This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).