Microscopic Polyangiitis Presenting with Uncommon Reversed Halo Sign: A Case Report

This case report presents an uncommon manifestation of microscopic polyangiitis (MPA) characterized by an initial reversed halo sign (RHS) on chest computed tomography (CT).A 49-year-old female patient with a history of sensorineural hearing loss presented with progressive respiratory symptoms.Comprehensive clinical investigations, including chest CT, laboratory tests and renal biopsy, confirmed a diagnosis of MPA, and targeted treatment with glucocorticoids and cyclophosphamide resulted in significant improvement in the lung lesions.This report aims to increase clinical awareness of atypical presentations of MPA and to reduce potential diagnostic challenges.