What question did this study set out to answer?

This research aims to highlight the occurrence of pulmonary nodules in a patient with microscopic polyangiitis and the implications for treatment.

April 23, 2026Open Access

Pulmonary nodules in a case of microscopic polyangiitis: a case report and review of the literature

Key Points

This research aims to highlight the occurrence of pulmonary nodules in a patient with microscopic polyangiitis and the implications for treatment.
Description of a clinical case involving a 31-year-old female with MPA.
Use of renal biopsy and antibody detection for diagnosing ANCA-associated vasculitis.
Computed tomography scans to visualize pulmonary nodules.
Anti-MPO and anti-GBM antibodies confirmed MPA diagnosis.
Pulmonary nodules initially raised concerns for lung cancer.
Treatment with steroids and cyclophosphamide led to rapid symptom improvement and significant nodule size reduction.

Abstract

Microscopic polyangiitis (MPA) is a type of small-vessel vasculitis that can lead to organ damage, primarily affecting the kidneys and lungs. We described a 31-year-old female of East Asian ethnicity exhibiting fever, reduced appetite, fatigue, proteinuria, hematuria, and renal function impairment. Renal biopsy, along with the detection of anti-MPO (myeloperoxidase)-ANCA (anti-neutrophil cytoplasmic antibodies) and anti-GBM (glomerular basement membrane) antibodies, confirmed the diagnosis of ANCA-associated small-vessel vasculitis with renal injury, specifically Type III crescentic glomerulonephritis, namely MPA. Concurrently, the chest computed tomography (CT) of this patient revealed pulmonary nodules, raising initial suspicions of lung cancer. However, following a regimen of steroids and cyclophosphamide, the patient experienced a rapid improvement in symptoms, and a significant reduction in the size of the pulmonary nodules, ultimately avoiding the resection surgery. This case highlights the critical need for accurate differentiation of pulmonary nodules in MPA patients, ensuring timely and appropriate treatment.

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