Cavernous carotid artery aneurysm (CCA) is rare, comprising less than 2% of all intracranial aneurysms. CCAs typically present with mass effect and rarely cause epistaxis (<3%). This report presents a case of a left side CCA eroding into the paranasal sinuses, causing recurrent nasal bleeding, discovered after the onset of a cranial nerve deficit.

A 93-year-old female presented to the hospital with a large-volume recurrent epistaxis, accompanied by new-onset left frontal headache, left eye pain with progressive ptosis, visual blurring, and fatigue over four days. Left-eyelid ptosis with ophthalmoplegia, and mild tenderness over the left temple was noted on initial physical examination. The epistaxis was initially managed with nasal packing for temporary hemostasis. A head CT demonstrated hypoattenuation in the left sphenoid sinus, raising concern for fungal mass versus inspissated material. The patient was empirically started on antibiotics and corticosteroids concerning possible infection and/or GCA.

Subsequent imaging with CT angiography (CTA) revealed mild to moderate stenosis of the proximal cavernous segment and a multilobulated aneurysm eroding into the left sphenoid sinus. A cerebral angiogram confirmed the aneurysm as the source of bleeding and the patient underwent endovascular embolization using balloon-guided coiling with protection of the herniated segment. Post-procedural angiography showed a secured rupture site with preservation of intracranial circulation.

The patient demonstrated persistent signs of left cavernous sinus syndrome (ptosis and ophthalmoplegia) but experienced no further episodes of epistaxis. Due to progressive functional decline and personal preference, she refused additional life-sustaining treatment, including flow diversion for symptom relief, and elected to transition to hospice care.

CCA rupture is rare but should be included in the differentials for recurrent, large-volume epistaxis when no nasal pathology or coagulopathy is identified. While immediate hemostasis is critical, early diagnosis and timely intervention are essential to reduce morbidity/mortality.