284. A Study of Morphea in Systemic Sclerosis: Defining Links Between Localized and Systemic Sclerosis

Background: Some patients with SSc develop skin features of localized scleroderma. One clinical subtype, keloid/nodular morphea, is particularly challenging to treat and may offer insight into key pathogenetic mechanisms. We have identified a cohort of SSc cases with concurrent localized scleroderma and examined their clinical and laboratory features and undertaken gene expression analysis to define the underlying pathogenic mechanism. Methods: We examined a clinical database of 2200 patients with SSc to identify all patients with a clinical or histological diagnosis of localized scleroderma and SSc overlap. The demographics, clinical features and serology of these patients were examined in detail. We undertook gene expression analysis of forearm and keloid/nodular morphea lesional skin biopsies from six patients by RT-PCR for matrix genes including COMP and thrombospondin-1, skin biopsies from patients with early or established diffuse cutaneous SSc provided a control group. Results: 49 patients (2.2%) had evidence of localized scleroderma and SSc. Demographic and clinical data from this group were broadly comparable to the SSc cohort, excepting higher prevalence in females (female: male ratio 11:1). Limited: diffuse cutaneous SSc ratio was 2:1 which is representative of this SSc cohort. Three subtypes of localized scleroderma were prevalent in this patient group: plaque morphea in 32 patients (67%); linear morphea of trunk and limbs in 4 patients (8.0%) and keloid/nodular morphea in 12 patients (25%). 28 out of 32 patients with plaque morphea and 3 out of 4 patients with linear morphea had limited cutaneous SSc, while 11 out of 12 subjects with keloid/nodular morphea had diffuse cutaneous SSc (P<0.001). There were no clear serological associations when correcting for subset. Black ethnicity, as could be expected, was prevalent in patients with keloid/nodular morphea (58% of keloid patients compared with 4% in our SSc cohort). Keloid nodules were localized on the upper chest, breast and upper limbs. Demographic, clinical and serological data are summarized in Table 1. Gene expression analysis defined key markers of matrix over expression compared with early stage or established SSc lesional skin. Conclusion: This is the largest analysis of localized scleroderma in SSc to be presented. There are particular associations of subtypes of localized scleroderma with subsets of SSc which are not related to serology. Paired gene expression of keloid and non-keloid SSc skin will contribute to an understanding of pathogenesis of this rare but important complication. Disclosure statement: The authors have declared no conflicts of interest.