Spontaneous Healing of a Ruptured Blood Blister-Like Aneurysm

BACKGROUND: Blood blister-like aneurysms (BBAs) are an uncommon group of arterial aneurysms with a high risk of rupture, progression, and repeat rupture. The best intervention is unclear; however, their clinical behavior typically requires urgent intervention. We describe a BBA managed conservatively with complete resolution found at follow-up. CASE DESCRIPTION: A 50-year-old woman presented with a Hunt-Hess grade 2, Fisher grade 3 subarachnoid hemorrhage (SAH). Computed tomography (CT) revealed mild hydrocephalus with a thick basal SAH that was eccentric to the left. The findings from CT angiography were negative. Digital subtraction arteriography (DSA) revealed a focal protuberance along the dorsal surface of the left ophthalmic segment that was concerning for a dorsal variant BBA. Repeat angiography 48 hours later demonstrated receding of the ectasia, with replacement by a <1-mm defect resembling a dorsal vessel surface fenestration. DSA 7 days after her presentation showed further healing. At 6 weeks, DSA showed no residual abnormality. CONCLUSIONS: DSA remains an important imaging study for the detection of small aneurysms, because CT angiography might not have sufficient resolution. Our unique case provides strong evidence that BBAs represent a parent artery focal dissection. BBAs can remodel over time, usually with enlargement and repeat rupture if untreated. It is possible, as we have demonstrated, that some small lesions presenting with SAH might spontaneously heal without intervention.