Endoscopic Management of Intraventricular Brain Tumors in Children

Abstract

Endoscopic procedures for children with brain tumors include tumor cyst fenestration, tumor biopsy, tumor removal, and metastatic disease assessment. Most children with intraventricular tumors have concomitant hydrocephalus. This makes endoscopic surgery particularly attractive since simultaneous procedures can be employed both for CSF diversion and tumor management.

Transventricular endoscopic tumor cyst decompression can temporarily or permanently alleviate obstructive hydrocephalus or visual loss. It can be employed for craniopharyngiomas, hypothalamic/chiasmatic astrocytomas, and suprasellar germ cell tumors.

Endoscopic tumor biopsy is a well-established method for sampling intraventricular brain tumors. It has high diagnostic yield (98 %) and low risk (<2 %). Germ cell tumor, infiltrative hypothalamic/optic pathway glioma, and Langerhans cell histiocytosis are suitable for endoscopic biopsy. Only tumors that exhibit an exophytic component into the ventricle are candidates for endoscopic biopsy.

Primary central nervous system germ cell tumors (CNS GCT), both pure germinomas and nongerminomatous germ cell tumors, can be effectively treated without radical resection. Thus, children who present with noncommunicating hydrocephalus with a pineal region tumor should be considered always for primary endoscopic management with ETV and tumor biopsy. Serum biochemical analysis for alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) should always precede endoscopic biopsy since marker-positive GCT should be managed initially with neo-adjuvant chemotherapy. When performing simultaneous ETV and tumor biopsy, it is preferred to perform the ETV prior to tumor biopsy.

Solid tumor removal is limited due to the inadequacy of compatible instrumentation and the small caliber of current endoscopic portals. The success of endoscopic tumor removal is dependent upon the tumor characteristics including size, density, and vascularity. Tumors larger than 2 cm, those that have appreciable calcification on computed tomography (CT), and those that have significant subependymal infiltration are not currently amenable to endoscopic removal. Suitable for endoscopic removal are colloid cysts and larger tumors that are pedunculated at the ependymal surface.

Tumor dissemination observed during endoscopic surgery has recently been highlighted in patients with germ cell tumors in which the preoperative magnetic resonance imaging failed to exhibit metastatic disease.

Overall, the potential of endoscopic surgery for intraventricular brain tumors is expected to expand with technological advancements in compatible instrumentation.