Abstract Details

Title Rare Intronic BRAF Gene Fusion in a Recurrent Parietal Pleomorphic Xanthoastrocytoma: A Case Report

Topic Neuro-oncology

Presentation(s) P7 - Poster Session 7 (8:00 AM-9:00 AM)

Poster/Presentation
Number 6-009

Objective NA

Background Pleomorphic xanthoastrocytoma (PXA) is a rare primary astrocytic tumor typically affecting
children and young adults. We present the case of a 39-year-old female with recurrent parietal
PXA exhibiting an unusual BRAF genetic rearrangement. The patient initially presented with
exacerbating headaches, vomiting, photophobia, tinnitus, neck pain, and left-sided weakness.
Over five years, the patient underwent multiple resections, radiation therapies, stereotactic
radiosurgeries, and targeted treatments, including vemurafenib, dabrafenib, and trametinib.
Disease progression persisted, ultimately leading to a biopsy confirming tumor extension into the
scalp along the biopsy tract.

Design/Methods NA

Results

Pathology confirmed borderline grade III PXA with a BRAF V600E mutation. Neuro-oncology targeted next-generation sequencing revealed a BRAF gene rearrangement. The detected fusion event joined exon 18 of BRAF gene (5' partner) with exon 10 of BRAF (3' partner).

Conclusions This rearrangement, not previously reported in PXA, potentially contributed to the tumor's
aggressive and recurrent behavior. Two hypotheses for scalp metastasis include tumor spread
along the biopsy tract or contamination during resection. The aggressive characteristics of the
tumor may have enabled its survival outside the original tumor microenvironment.

The timing of the BRAF rearrangement remains unclear, limiting conclusions about its role in
the tumor’s progression. This case underscores the need for further studies to elucidate the
clinical and prognostic implications of BRAF fusions in PXA.

Authors/Disclosures
Daniel Mansour PRESENTER	Mr. Mansour has nothing to disclose.
Ankita Singh, MD-PhD Student	Miss Singh has nothing to disclose.
Liam Chen, MD, PhD	Dr. Chen has nothing to disclose.

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