Fatal ornithine transcarbamylase deficiency presentation postresection of fourth ventricle ependymoma: illustrative case

This case describes a novel presentation of late-onset OTCD triggered by posterior fossa craniectomy for resection of a fourth ventricular ependymoma-an association not previously reported in the literature. It emphasizes the importance of maintaining an index of suspicion for metabolic disorders in the setting of postoperative hyperammonemia. Future steps should focus on early testing of ammonia levels in patients with unexplained neurological decline to be proactive with multidisciplinary management. https://thejns.org/doi/10.3171/CASE25324.