Lateral medullary syndrome (LMS) typically spares motor pathways. Opalski syndrome is a rare variant characterized by ipsilateral hemiparesis due to caudal extension of infarction below the pyramidal decussation. We report a 55-year-old male presenting with vertigo, dysarthria, ataxia, ipsilateral hemiparesis, and contralateral sensory loss. MRI revealed infarction of the right posterolateral medulla with bilateral cerebellar involvement, while CT angiography demonstrated a hypoplastic and occluded right vertebral artery with non-visualization of the posterior inferior cerebellar artery. The patient developed bulbar dysfunction requiring ventilatory support and had a severe clinical course. This case highlights ipsilateral hemiparesis as a diagnostic pitfall and suggests that extensive vascular involvement and bilateral cerebellar infarction may be associated with poorer outcomes in Opalski syndrome.

Written informed consent was obtained from the patient's legally authorized representative for publication of this case report and accompanying images. Institutional ethical approval was waived as per local policy for single case reports.

V.G. developed the concept and design, drafted the manuscript, reviewed the literature, and did the clinical data acquisition. P.G. contributed toward radiological interpretation of the data. V.G. and P.G. critically revised the manuscript and gave the final approval of the manuscript.

Article published online:
07 May 2026

© 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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