Correlation between disease activity and serum ferritin in clinically amyopathic dermatomyositis with rapidly-progressive interstitial lung disease: a case report

BACKGROUND: Clinically amyopathic dermatomyositis with anti-Melanoma Differentiation-Associated gene 5 (MDA5) antibody often presents with severe interstitial lung disease. Although serum ferritin level is known to reflect interstitial lung disease activity, there are few case reports describing this association. CASE PRESENTATION: A 58-year-old man was referred to our outpatient clinic with a 3-week history of cough and respiratory distress. He had erythema over the V area of the neck and a Gottron’s sign. Chest computed tomography revealed diffuse ground-glass opacities and reticular shadows in both lungs. Test for anti-MDA5 antibody was positive. After admission, he received triple combination therapy (methylprednisolone pulse therapy, tacrolimus, and cyclophosphamide). However, his respiratory condition worsened as the serum ferritin level increased. Despite no apparent deterioration on chest radiography, he ultimately died due to respiratory failure. CONCLUSIONS: In this case, triple combination therapy was not effective for the patient’s respiratory condition. The serum ferritin level was correlated with disease activity and was more useful than chest radiography for monitoring clinical status.