Abstract
BACKGROUND: Hamartomas of the floor of the fourth ventricle (HFFVs) are rare lesions that cause a variety of symptoms, including hemifacial spasm (HFS). When symptomatic, these deep-seated lesions are traditionally treated via open surgical approaches. The authors describe successful laser interstitial thermal therapy (LITT) of an HFFV causing intractable HFS. OBSERVATIONS: A healthy 19-month-old girl presented with right HFS, present since birth, occurring continuously throughout the day. MRI revealed a right HFFV. Following an unsuccessful trial of medical treatment and serial imaging to rule out a neoplastic process, she underwent LITT of the HFFV with immediate resolution of her facial spasm. She was discharged on postoperative day 1 with durability of her treatment at the 1-year follow-up and no neurological complications. LESSONS: Laser ablation of HFFVs provides a well-tolerated, durable treatment option for HFFVs in pediatric patients. https://thejns.org/doi/10.3171/CASE24721.