Early assessment of rapidly progressive interstitial pneumonia associated with amyopathic dermatomyositis

Amyopathic dermatomyositis (ADM) is occasionally complicated by rapidly progressive interstitial pneumonia (RPIP), and in such cases, diffuse alveolar damage (DAD) is usually diagnosed at autopsy. Here, we present three patients with RPIP accompanied by ADM in whom lung disease was assessed at an early stage. High-resolution computed tomography (HRCT) carried out before the onset of dyspnoea revealed uniformly subpleural reticular opacity with faint ground-glass attenuation. At that stage, surgical lung biopsies from two patients showed histological patterns typical of cellular nonspecific interstitial pneumonia (NSIP). Despite pulse methylprednisolone and subsequent high-dose oral administration of prednisolone, lung disease progressed in all patients, with extensive areas of ground-glass opacity and consolidation observed in HRCT scans. DAD was confirmed histologically in one case. Additional administration of cyclosporine, pulse cyclophosphamide or high-dose intravenous administration of immunoglobulin rescued all patients. Our data suggest that ADM-associated interstitial pneumonia takes an aggressive course even when the radiological and histological features are consistent with NSIP. Aggressive combination therapy with high-dose steroids and immunosuppressive agents is required as early as possible for patients with this life-threatening disorder.