Scleroderma-polymyositis overlap syndrome versus idiopathic polymyositis and systemic sclerosis: a descriptive study on clinical features and myopathology

Abstract

IntroductionThe objective was to characterize the clinical and myopathologic features of patients with scleroderma-polymyositis (SSc-PM) overlap compared with a population of patients with systemic sclerosis (SSc) and polymyositis (PM).MethodsA three-way comparison of patients with SSc-PM overlap (n = 25) with patients with SSc (n = 397) and PM (n = 40) on clinical and myopathologic features and causes of death. One neuropathologist blinded for the diagnosis evaluated all recent available muscle biopsies. Biopsies were scored for presence of inflammation, necrotic muscle fibers, rimmed vacuoles, fibrosis, and immunohistochemical staining. Clinical or myopathologic characteristics were compared by using the χ2 test or one-way analysis of variance (ANOVA).ResultsThe prevalence of SSc-PM overlap in the Nijmegen Systemic Sclerosis cohort was 5.9%. The mortality was 32% (eight of 25) in SSc-PM, of which half was related to cardiac diseases. The prevalence of pulmonary fibrosis was significantly increased in SSc-PM (83%) (P = 0.04) compared with SSc (49%) and PM (53%). SSc or myositis-specific antibodies were nearly absent in the SSc-PM group. In almost all biopsies (96%) of SSc-PM patients, necrotic muscle fibers were present, which was significantly increased compared with PM patients (P = 0.02).ConclusionsPatients with SSc-PM have increased prevalence of pulmonary fibrosis and cardiac disease as the cause of death compared with patients with SSc and PM . In addition, we found that necrotizing muscle fibers with inflammation characterize SSc-PM overlap in muscle biopsies. Further research should focus on underlying mechanisms causing necrosis, inflammation, and fibrosis and their relation to pulmonary involvement and mortality in patients with SSc-PM overlap.

Spectrum of Muscle Histopathologic Findings in Forty‐Two Scleroderma Patients With Weakness

“…Additional immunostaining in our study revealed increased MHC I expression in more than half of the biopsies. Although positive MHC I staining (up to 92%) has been reported by Bhansing and colleagues in scleroderma patients with polymyositis overlap (14), this is the first report of increased MHC I expression in a more diverse collection of weak scleroderma subjects.…”

“…In one large well-characterized scleroderma cohort, 1.3% (2/1,499) of SSc patients satisfied the 1975 Bohan and Peter diagnostic criteria for definite PM/DM (13). A range of muscle biopsy features have been described including inflammation and prominent necrosis (14,15). One study suggested that fibrosis was the prominent finding in muscle biopsies of weak scleroderma patients (16).…”

Overlap myositis, a distinct entity beyond primary inflammatory myositis: A retrospective analysis of a large cohort from the REMICAM registry

“…Interestingly, 47 OM patients (48%) developed ILD during follow‐up, which is significantly higher than in PM and DM patients (35% and 30.8%, respectively). Similarly, Bhansing et al described a significantly increased prevalence of pulmonary fibrosis in the overlap group compared to PM and primary SSc patients (83%, 53% and 49%, respectively). Other authors compared the clinical and serological features of myositis patients with and without overlap, and confirmed a higher frequency of extramuscular involvement in OM, supporting the hypothesis of a distinct entity …”

Systemic sclerosis: An update in 2016

“…Patients with anti-PmScl antibodies have overlap syndromes between myositis and scleroderma. They are more likely to have myopathy and pulmonary disease [24]. Patients with scleroderma and anti-PmScl antibodies had fewer digital ulcers and cutaneous thickening or diffuse form while they had better pulmonary prognosis [25].…”