Ventrolateral pontomedullary junction cavernous malformation: illustrative case.

backgroundVentrolateral pontomedullary junction (PMJ) cavernous malformations are surgically challenging because of their proximity to the corticospinal tracts, vertebral artery, and lower cranial nerves. Optimal corridor selection and preservation of eloquent tracts remain critical to minimize morbidity. OBSERVATIONS: A 40-year-old woman presented with acute-onset horizontal diplopia. MRI demonstrated a left ventrolateral PMJ cavernous malformation with pial surface presentation and evidence of prior hemorrhage. Diffusion tensor imaging revealed displaced but preserved corticospinal tracts. A modified far-lateral approach with limited occipital condyle drilling allowed direct access through the lower cranial nerve-hypoglossal interval. Wide pial opening and mobilization of the lesion toward the surface facilitated resection along the lesion-brain plane under continuous neurophysiological monitoring. Gross-total resection was achieved. Abducens palsy transiently worsened but improved beyond the preoperative baseline. No new permanent deficits occurred. LESSONS: In selected ventrolateral PMJ cavernous malformations with surface presentation, a tailored far-lateral corridor combined with deliberate lesion mobilization toward the pial opening may permit safe resection while minimizing traction on eloquent tracts. https://thejns.org/doi/10.3171/CASE26206.