Spontaneous hemorrhage of cavernous malformation in the region of the cochlear nucleus: A case report.

Cerebral cavernous malformations (CMs) are low-flow, thin-walled vascular lesions affecting approximately 0.5%-0.9% of the population; they rarely arise at the skull base, and involvement of the cerebellopontine angle (CPA) is exceptionally uncommon, with only 19-21 cases reported and no prior description of cochlear nucleus involvement. We report a previously healthy 33-year-old woman who presented acutely with right-sided temporal headache, severe vertigo, sensorineural hearing loss, otalgia, and facial weakness. Multisequential MRI, including susceptibility-weighted imaging (SWI), demonstrated a hemorrhagic CM centered on the right cochlear nucleus with CPA extension and a co-existing developmental venous anomaly, allowing confident noninvasive diagnosis. She was managed conservatively with corticosteroids and multidisciplinary follow-up; at 1-year, facial weakness and vertigo had fully resolved, but severe-to-profound sensorineural hearing loss persisted. To the best of our knowledge, this represents one of the very few, if not the first, reported cases of hemorrhagic CM confined to the cochlear nucleus with CPA extension, underscoring the value of multisequential MRI in avoiding unnecessary invasive procedures.