Pontine Tegmental Infarction With Cerebellar Involvement Mimicking Lateral Medullary Syndrome: A Clinico-Radiological Paradox.

Lateral medullary syndrome (LMS), or Wallenberg syndrome, typically arises from ischemia of the dorsolateral medulla and is characterized by crossed sensory deficits, ipsilateral cranial nerve involvement, cerebellar ataxia, and Horner's syndrome. We report a 66-year-old hypertensive female who presented with classical clinical features suggestive of LMS, including ipsilateral facial sensory loss, contralateral body sensory impairment, palatal weakness, ipsilateral Horner's syndrome, and cerebellar signs. However, diffusion-weighted magnetic resonance imaging revealed a predominantly paramedian pontine tegmental infarction with associated right cerebellar involvement, without evidence of medullary ischemia. This clinico-radiological dissociation can be explained by the involvement of shared neuroanatomical pathways, such as the spinothalamic tract, spinal trigeminal nucleus, and descending sympathetic fibers, which extend into the pontine tegmentum, thereby mimicking LMS. This case highlights the limitations of clinical localization in posterior circulation stroke and emphasizes the importance of neuroimaging in accurately identifying lesion sites when brainstem syndromes present with overlapping features.