To describe a rare presentation of microscopic polyangiitis (MPA) manifesting with central retinal artery occlusion (CRAO) and brainstem infarction, emphasizing the importance of early recognition and multidisciplinary management of atypical vasculitic complications. 

MPA is an antineutrophil cytoplasmic antibody (ANCA) associated small-vessel vasculitis primarily affecting the kidneys, lungs, and peripheral nerves. Central retinal artery occlusion is an uncommon ophthalmic emergency resulting from vascular occlusion and is rarely linked to systemic vasculitis. Concurrent CRAO and brainstem infarction in MPA have been scarcely reported, underscoring the need for heightened diagnostic vigilance.

We report a single-patient case with clinical, radiological, and histopathological correlation. Diagnostic work-up included MRI brain, fundus examination, nerve conduction studies, ANCA serology, and renal biopsy. Treatment response to corticosteroids and immunosuppressive therapy was observed over follow-up.

A 50-year-old woman presented with acute painless unilateral vision loss, left-sided foot drop, and constitutional symptoms. MRI revealed a right pontine infarct; fundus examination confirmed CRAO. Laboratory tests showed elevated ESR, CRP, and creatinine, with positive p-ANCA. Renal biopsy demonstrated pauci-immune necrotizing glomerulonephritis, establishing the diagnosis of MPA. The patient was treated with pulse methylprednisolone followed by cyclophosphamide, resulting in improvement of systemic and neurological symptoms but persistent visual loss.

This case highlights a rare coexistence of CRAO and brainstem infarction secondary to MPA. Early suspicion of vasculitis in patients with unexplained ischemic events can facilitate timely immunosuppressive therapy, potentially improving outcomes. Recognition of such atypical presentations broadens understanding of MPA’s vascular spectrum and emphasizes the value of a collaborative diagnostic approach.