Acute Binocular Diplopia with Ataxia: MRI Diagnosis of Facial Colliculus Syndrome with Selective Abducens Nuclear Involvement

Abstract: Background: Facial colliculus syndrome (FCS) is an uncommon dorsal pontine syndrome resulting from lesions at the level of the facial colliculus. It classically presents with ipsilateral horizontal gaze palsy and lower motor neuron facial weakness due to involvement of the abducens nucleus and facial nerve fascicle¹,². Selective abducens nuclear involvement without facial palsy is rare. Case Presentation: A 65-year-old male presented with acute binocular horizontal diplopia and gait imbalance. Neurological examination revealed impaired conjugate horizontal gaze toward the left side without facial weakness. MRI demonstrated a focal diffusion-restricting lesion in the dorsal caudal pons at the level of the facial colliculus. Imaging findings confirmed acute infarction selectively involving the abducens nucleus. Conclusion: This case highlights an incomplete variant of facial colliculus syndrome. Diffusion-weighted MRI plays a pivotal role in detecting small brainstem infarcts and accurately localizing dorsal pontine lesions. Keywords: Facial colliculus syndrome; Abducens nucleus; Pontine infarction; Brainstem stroke; Diplopia; MRI. Title: Acute Binocular Diplopia with Ataxia: MRI Diagnosis of Facial Colliculus Syndrome with Selective Abducens Nuclear Involvement Author: Dr Ishfaq Nazir, Dr Bisma Fayaz, Dr Aqib Manzoor International Journal of Healthcare Sciences ISSN 2348-5728 (Online) Vol. 13, Issue 2, October 2025 - March 2026 Page No: 428-432 Research Publish Journals Website: www.researchpublish.com Published Date: 25-February-2026 DOI: https://doi.org/10.5281/zenodo.18770502 Paper Download Link (Source) https://www.researchpublish.com/papers/acute-binocular-diplopia-with-ataxia-mri-diagnosis-of-facial-colliculus-syndrome-with-selective-abducens-nuclear-involvement