Lung histopathological pattern in a survivor with rapidly progressive interstitial lung disease and anti-melanoma differentiation-associated gene 5 antibody-positive clinically amyopathic dermatomyositis

Abstract

Anti-melanoma differentiation-associated gene 5 (MDA5) antibodies are specific indicators of patients with dermatomyositis, particularly clinically amyopathic dermatomyositis (CADM). CADM is occasionally accompanied by fatal, treatment-resistant, rapidly-progressive interstitial lung disease (RP-ILD). All previous reports showed that histopathological findings in RP-ILD with anti-MDA5 antibody-positive CADM indicated diffuse alveolar damage (DAD). This is the first report describing a non-DAD pattern in RP-ILD with anti-MDA5 antibody-positive CADM, which was improved by immunosuppressive therapy. This case may be a milder clinical phenotype than a typical DAD pattern in RP-ILD with anti-MDA5 antibody-positive CADM.

Keywords: 6MWD, six-min walk distance; CADM; CADM, clinically amyopathic dermatomyositis; CT, computed tomography; DAD; DAD, diffuse alveolar damage; DLco, diffusing capacity of the lung for carbon monoxide; FVC, forced vital capacity; IVCY, intravenous cyclophosphamide; Lung histopathological pattern; MDA5; MDA5, melanoma differentiation-associated gene 5; MMRC, modified medical research council dyspnea scale; NSIP, nonspecific interstitial pneumonia; RP-ILD; RP-ILD, rapidly progressive interstitial lung disease.

Fig. 1

Physical findings suggestive of clinically amyopathic dermatomyositis. a) facial erythema and heliotrope rash; b) erythema over the V area of the neck; c) scaly erythema with ulceration over the elbow; d) Gottron’s sign.

Fig. 2

Chest computed tomography. Peribronchovascular ground-glass opacities and bilateral subpleural reticular opacities.

Fig. 3

Histopathological findings in lung biopsy specimen. a) diffuse involvement in secondary lobule with mild peripheral accentuation [haematoxylin-eosin (HE) stain]; b) accumulation of foamy macrophages accentuated in the periphery of the lobule along with a few neutrophils [HE stain]; c) no hyaline membrane or extensive fibrin are seen, but rare and scant airspace fibrin is found [HE stain]; d) Scattered Masson bodies as organizing pneumonia incorporating surrounding alveolar ducts in less than 20% of area [Elastica van Gieson stain]. Scale bars: 900 μm (a), 200 μm (b, c, d).