OBJECTIVE To compare the clinical and laboratory features of pediatric systemic sclerosis sine scleroderma (ssJSSc) with adult-onset ssSSc. METHODS Demographic, clinical and laboratory data of ssJSSc, retrospectively retrieved from our hospital medical records, case reports from the literature and from the PRES JSSc registry, were compared with the Padua cohort of adult patients with ssSSc. Patients were defined as having ssSSc if they never had skin involvement but all the following features: (I) Raynaud's Phenomenon (RP) and/or digital vasculopathy, (II) positive antinuclear antibodies (ANA), (III) internal organs involvement typical of scleroderma, (IV) no other defined connective tissue diseases. RESULTS Eighteen juvenile and 38 adult-onset ssSSc patients, mean disease duration 5.8 and 9.7 years, respectively, entered the study. The frequency of females affected was significantly lower in ssJSSc (38.9% vs 89.5%, p < 0.0001). When compared to adults, ssJSSc displayed less SSc-specific capillaroscopy abnormalities (68.8% vs 94.7%, p = 0.02) while significantly higher vascular (digital pitting scars, ulcers 35.3% vs 10.5%, p = 0.042), respiratory (50.0% vs 23.7%, p = 0.02) and cardiac involvement (50.0% vs 2.6%, p < 0.0001). The outcome was significantly worse in ssJSSc as six patients (33%) died (n = 3) or reached an end-stage organ failure (n = 3) in comparison to only two deaths (5.3%) in the adult cohort. Anti-centromere antibodies were significantly lower in children (20.0% vs 68.4%, p = 0.001) while no difference was noted for other SSc-specific autoantibodies. CONCLUSIONS Compared to adults where ssSSc generally has an indolent course, children present with aggressive disease that heralds a worse prognosis characterized by high cardiorespiratory morbidity and mortality.Key Indexing Terms: scleroderma, juvenile systemic sclerosis, outcome, heart, pulmonary arterial.