Direct Ethanol Puncture Technique for Preoperative Embolization of Bulky Skull Base Sarcoma: Case Report

Introduction: Large exophytic tumors can be technically challenging because of the bulky nature of the mass and potential blood loss. Absolute ethanol can be used in these scenarios to create an immediate sclerosis of the intratumoral vessels, allowing the surgeon to proceed with resection without delay.

History: A 60-year-old female patient presented with a hemorrhagic, spherical exophytic mass originating from the right pinna, measuring approximately 8 cm in diameter. Outside needle biopsy demonstrated sarcoma, likely induced by prior radiation 6 years before treating a parotid tumor. The large external component subsumed the entire ear, and extended transtemporally to merge with a second intradural component within the middle and posterior fossae.

Intervention: Transcatheter preoperative embolization was performed via middle meningeal and local branches of the external carotid artery using polyvinyl alcohol. The next day, under general anesthesia, the tumor was directly punctured at three separate sites with 18-guage spinal needles from the external surface. After performance of angiography to assess run-off, 2 mL of absolute ethanol was injected at each site. Within minutes, the tissue became wooden, firm, and avascular in a region for 2 to 3 cm surrounding the needle tip. Resection was easily performed by paring the tumor away with a number 11 blade.

Discussion: Direct ethanol puncture can achieve rapid devascularization of bulky tumors. Extreme caution must be taken to limit the spread of the ethanol into areas containing potentially functional structures. A clear understanding of the estimated pattern of spread of the ethanol, as demonstrated in the image aforementioned during contrast injection, is essential to perform the technique safely.