Histopathology and immunohistochemistry of depigmented lesions in lupus erythematosus / Análise histopatológica e imunohistoquímica das lesões vitiligóides no lúpus eritematoso cutâneo

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

27/04/2011

RESUMO

Lupus Erythematosus (LE) is an autoimmune disorder with multiple clinical manifestations. Skin damage is a hallmark of the disease. Cutaneous LE (CLE) includes acute LE (ACLE), subacute LE (SCLE) and chronic LE (CCLE). Although achromic lesions are often found in patients with LEC, there are no detailed data about the histological features of such lesions. Therefore, we designed this study to determine clinical, laboratorial and histological profile of patients with LEC presenting achromic lesions. Between 2005 and 2008, we identified 12 individuals with LEC and acromic lesions from a larger group of 220 patients with LEC that were followed at the Dermatology outpatient clinic. There were seven patients with LECC and five with LECSA. Twelve patients with chronic stable vitiligo and 10 controls of unaffected skin were used for comparison. The most frequent histological abnormalities found in LEC-related achromic lesions were inflammatory infiltrates (75%); hyperkeratosis and thickening of the basement membrane (BM) (66.7%); epidermal flattening (58.3%); apoptotic epidermal keratinocytes, elastosis and vasodilation (50%); fibrosis (41.7%); hydropic degeneration of the basal cells (33.3%); follicular plugging (16.7%). These achromic lesions retained histological features that enabled the diagnosis of CLE to be established in four patients. Fontana Masson (FM) staining was positive for melanin in five cases and revealed pigmentary incontinence in four. Immunohistochemistry for HMB45 and Melan-A identified melanocytes in five CLE-related achromic lesions. Melanocyte counts were significantly smaller in achromic lesions when compared to unaffected skin samples. When compared to vitiligo, CLE-related achromic lesions showed more frequently apoptotic epidermal keratinocytes (p=0,014), thickening of the BM (p=0,009) and fibrosis (p=0,037). Melanocyte counts according to immunohistochemistry were similar in CLE and vitiligo groups. Our results indicate that CLE-related achromic lesions represent residual scars due to chronic lichenoid inflammation that leads to melanocyte destruction. Melanocyte count does not help to distinguish CLE-related achromic lesions and true vitiligo lesions. Despite this, HMB45 staining was sometimes positive in both conditions, which indicates active melanogenesis and suggests that repigmentation may be possible at least for some individuals

ASSUNTO(S)

lúpus eritematoso cutâneo vitiligo histologia cutaneous lupus erythematosus vitiligo histopathology imunoistoquímica immunohistochemistry

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