Microsurgical excision of a giant cerebellopontine angle atypical teratoid/rhabdoid tumor in an 11-month-old infant: surgical video

Abstract

Atypical teratoid/rhabdoid tumor (ATRT) is an aggressive embryonal neoplasm of infancy that most often arises in the posterior fossa, where it may occupy the cerebellopontine angle and closely mimic more common pediatric tumors on imaging. Resection in this location is demanding because of the size of the lesion relative to the infant’s posterior fossa, its vascularity, and the intimacy of the tumor with the brainstem and the cranial nerves of the cerebellopontine angle. We present the operative video of an 11-month-old male infant with a 1-month history of projectile vomiting and 2 weeks of regression of acquired milestones, in whom imaging demonstrated a 4 _ 4 cm solid-cystic mass in the right cerebellopontine angle with brainstem and fourth ventricular compression and obstructive hydrocephalus. A ventriculoperitoneal shunt was placed through a left Frazier’s point burr hole in the emergency setting, and definitive tumor surgery was deferred by 1 week, during which hydration was corrected and a lower respiratory infection settled. The tumor was then approached through a hockey-stick incision and a suboccipital craniotomy extending 2 cm to the left and 4 cm to the right of the midline. At operation the lesion proved not to be purely extra-axial: it infiltrated the lower part of the right cerebellar hemisphere and the tonsil, filled the entire cerebellopontine angle, and distorted and rotated the brainstem. The tumor feeders were cauterized with preservation of the supply to the cerebellum and the brainstem, intratumoral decompression was carried out within a preserved arachnoid plane, and a cottonoid was placed in the fourth ventricle to prevent spillage of blood into the ventricular system. Near total excision was achieved, with a thin layer of tumor deliberately left on the brainstem and cranial nerves to avoid brainstem infarction and neurovascular injury. Histopathology established a Central Nervous System World Health Organization (CNS WHO) grade 4 ATRT. This video illustrates the operative sequence and the technical considerations relevant to the excision of a large cerebellopontine angle embryonal tumor in infancy.