A case of microscopic polyangiitis associated with unclassifiable interstitial pneumonia, in which myeloperoxidase anti-neutrophil cytoplasmic antibody became positive during the course of investigation
Ryo Sato Tomofumi Kobayashi Yuki Kawase Tatsuru Ishikawa Yuichiro Asai Hirofumi Chiba
Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine
A 65-year-old woman, in whom bilateral reticular shadows were detected on a chest radiograph at medical examination, was referred to our hospital for detailed examination. She had been complaining of weight loss, eruption and finger stiffness. Physical examination revealed bilateral lower leg edema and erythema on the left lower leg. Computed tomography of the chest showed bilateral perivascular ground-glass opacities and consolidations. Surgical lung biopsy was not performed. However, a biopsy specimen obtained from erythema on the left lower leg showed the findings of leukocytoclastic vasculitis. The myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) test was negative at the first visit, but, on subsequent examination, the MPO-ANCA test was positive, and microscopic polyangiitis (MPA) was diagnosed. She was successfully treated with systemic corticosteroids and cyclophosphamide. This is a rare case of unclassifiable interstitial pneumonia associated with MPA.
Microscopic polyangiitis (MPA) Unclassifiable interstitial pneumonia Skin biopsy Myeloperoxidase anti-neutrophil cytoplasmic antibody Positive conversion
Received 25 May 2020 / Accepted 5 Oct 2020
AJRS, 10(1): 69-73, 2021