A rare case of unilateral Cogan’s anterior internuclear ophthalmoplegia, upgaze palsy and ataxia caused by dorsal tegmentum lesion at pontomesencephalic junction

Abstract Background Cogan’s anterior internuclear ophthalmoplegia (INO) is characterized by INO with inability to converge and commonly thought be due rostral midbrain lesion. A lesion outside that causes unilateral combined upgaze palsy ataxia are rarely described. Case presentation 67-year old male presented left (INO), appendicular bilateral palsy. Magnetic Resonance Imaging (MRI) Angiography (MRA) brain showed a dorsal tegmental infarct at the level of pontomesencephalic junction. Conclusions This case highlights clinical importance in combination ataxia, report possible site patients such constellation. Clinicians should consider looking for cerebellar signs cases INO, apart from just considering localizing midbrain.