DIPG-56. BRAINSTEM TUMOR BIOPSY: A SINGLE INSTITUTE EXPERIENCE OF SAFETY AND FEASIBILITY IN A LOW-MIDDLE INCOME COUNTRY (LMIC)

Brainstem tumors account for 10-15% of all pediatric central nervous system tumors and carry a dismal prognosis. These include a wide spectrum of histological diagnosis therefore, in most specialized centers stereotactic biopsies for brainstem tumors are considered safe and standard practice. However, this approach continues to pose a challenge in LMIC’s.

We retrospectively reviewed data of patients presenting with brainstem tumors at Aga Khan University Hospital, Pakistan, between 2014 and 2023. In addition to histopathological analysis, whole-genome sequencing and RNA sequencing were also performed on 6 tumors.

We identified 39 patients with brainstem tumors; amongst these 56.4% were females. Median age at diagnosis was 9 years (IQR: 5.1-11). Most cases presented with walking difficulty (74%) and cranial nerve palsies (46%). Median duration of symptoms was 30 days (IQR: 20-60). On imaging large proportion were intrinsic pontine tumors (53.8%) followed by brainstem (30.8%) and cerebellopontine angle (15.4%). 21 patients underwent stereotactic biopsy with 86% performed after 2016. 43% were intrinsic pontine tumors. Histopathology analysis showed a wide spectrum with diffuse midline glioma in 28% of cases, pilocytic astrocytoma, anaplastic astrocytoma and ganglioglioma in 33%, 14% and 9% of cases respectively. Rare entities identified included embryonal tumor with multilayered rosettes, atypical teratoid rhabdoid tumor and schwannoma (5%). Biopsies were uneventful in 81% of cases. Complication of biopsy in 2 patients included cranial nerve palsy and subdural hemorrhage. No patient died due to complications of biopsy. Surgical and medical management was altered in 9 patients due to availability of histological diagnosis.

We present the first study demonstrating safety and feasibility of stereotactic biopsy for brainstem tumors in LMIC. These biopsies should be considered for atypical brainstem tumors and should be performed in well-equipped tertiary neurosurgical facilities by trained neurosurgeons in LMIC.