Delayed Clinical Response Following Intravenous Bleomycin Electrosclerotherapy for a High-Flow Glabellar Arteriovenous Malformation

High-flow arteriovenous malformations (AVMs), particularly in the facial region, present challenges to management due to the complex surrounding anatomy.Bleomycin electrosclerotherapy (BEST) is a treatment option for facial AVMs.In these instances, the bleomycin is most commonly administered intralesionally or via selective intra-arterial injection.We report the case of a 28-year-old man with a congenital glabellar AVM that has progressively enlarged and developed a palpable pulsation over the preceding few years.A soft tissue ultrasound and contrast-enhanced computer tomography (CT) confirmed a high-flow glabellar AVM with arterial feeders arising from the ophthalmic arteries and the external carotid arteries bilaterally.Due to the proximity of the ophthalmic arteries, direct sclerosant injection and embolisation were considered high risk for visual compromise.The patient underwent BEST under general anaesthesia, with 15,000 units of bleomycin administered intravenously followed by electroporation targeted to the lesion nidus.The procedure was completed without immediate complication.At eight weeks post-procedure, there was only marginal improvement in lesion size and pulsatility.However, at review six months later, there had been slow but progressive involution in both the size and pulsatility of the lesion, and no palpable pulsation was detected.This case demonstrates that BEST, whilst administered intravenously, may represent a treatment option for complex high-flow facial AVMs.In addition, clinicians should consider the time interval between treatment and follow-up, as the therapeutic response may be delayed, thus requiring extended follow-up before considering alternative treatment options.