Histological Changes of Linear Scleroderma “en Coup de Sabre”

Introduction. Scleroderma is a chronic disease of unknown aetiology characterized by skin fibrosis and is divided into two clinical entities: localized scleroderma and systemic sclerosis. But the localized scleroderma is not accompanied by Raynaud's phenomenon, acrosclerosis and internal organ involvement and the life prognosis of patients with localized scleroderma is good. Scleroderma “en coup de sabre” (ECDS) is considered a linear localized form of scleroderma or morphoea. It usually involves, unilaterally, the frontoparietal area, but may extend downwards to the face. Most cases begin before 10 years of age. The aim of our study was to investigate the histological characteristics and their clinical association in ECDS. Materials and methods. The present study was carried out at the Department of Dermatology and Venereology in Tbilisi State Medical University. 11 patients (2 men and 9 women) with lesions clinically and histologically diagnosed as ECDS were retrospectively included. Patients who were treated with immunomodulating agents, including systemic corticosteroids and immunosuppressants before presentation, or patients complicated with Parry – Romberg syndrome were excluded from the study. All patients were subjected to: history taking including: age, sex, duration of the disease, family history; clinical examination; skin biopsy – evaluated for epidermal atrophy, spongiosis, vacuolar degeneration of basal cell layer, satellite cell necrosis, basal pigmentation, melanin incontinence, perivascular infiltrate, perineural infiltrate, periappendageal infiltrate, vacuolar changes of follicular epithelium and dermal fibrosis. Results. All ECDS patients demonstrated epidermal lymphocytic infiltrate, tagging of lymphocytes along the dermo-epidermal junction and vacuolar changes, regardless of disease duration, clinical presentation and the intensity of perivascular lymphocytic infiltrate. Furthermore, when we defined patients with disease duration of < 3 years and of ≥ 6 years, respectively, the degrees of perivascular and/or peri-appendageal infiltrate and vacuolar changes of follicular epithelium were much greater, whereas epidermal atrophy was less frequently seen, in early ECDS patients than in late ECDS patients. The intensity of interface dermatitis in epidermis was comparable between early and late ECDS lesions. Also it's important to mention, that in our study in early stage localized scleroderma the characteristic histological finding is not only perivascular lymphocytic infiltrate. Vacuolar changes in epidermis is also a common histological feature in the sites of damaged skin of ECDS patients and vacuolar changes in follicular epithelium and peri-appendageal infiltrate serve as a histological marker of early and active ECDS lesions in addition to perivascular infiltrate. Conclusions. Although the pathogenesis of localized scleroderma still remains unknown, the present observation and received results are useful to determine the activity of skin lesions in ECDS and provide us a new clue to further understand the pathogenesis of this disorder.