Reappraisal of haemorrhagic suprasellar pilocytic astrocytoma during adulthood

Rare adult pilocytic astrocytoma of the septum pellucidum with novel RIN2::BRAF fusion

Pilocytic astrocytoma is mostly a pediatric tumor with the majority of patients under age 20. Although tumors can occur throughout neuraxis, most tumors are in the cerebellum and optic chiasm. Pilocytic astrocytoma in unusual locations is often associated with different genetic alterations than the classic KIAA1549::BRAF fusion. We report a rare adult pilocytic astrocytoma of the septum pellucidum that presented with progressive headache. A detailed genomic evaluation found a fusion between BRAF and a novel partner RIN2, a gene overexpressed in both low-grade glioma and glioblastoma. The RIN2::BRAF transcript encodes a chimeric protein containing a dimerization domain SH2 and an intact kinase domain, consistent with a prototypic oncogenic kinase rearrangement. In addition, we discuss the potential oncogenic mechanisms of BRAF signaling and its implication in targeted therapy with kinase inhibitors.

Optic Pathway–Hypothalamic Glioma Apoplexy: A Report of Two Cases and Systematic Review of the Literature

Background

Hemorrhage into optic pathway–hypothalamic glioma (OPHG) is rare. Variable clinical presentations and outcomes are associated with such pathology. We aim to present two infants presented with OPHG and a systematic review of the literature.

Methods

We describe two cases of infants presenting with sudden decreased vision, poor feeding, and irritability due to OPHG. Both patients underwent urgent craniotomy and subtotal resection followed by chemotherapy. We systematically reviewed the literature using PubMed, Google Scholar, and Embase. In addition, we included all English published reports for all ages discussing the optic pathway (optic nerve and optic chiasm) or hypothalamic glioma associated with hemorrhage from the year of the first reported case (1970) to January 2022.

Results

Of 17,949, 44 articles met the inclusion criteria of this review. A total of 56 cases were described with a mean of 21.35 years (0.5–70), with the male gender 52% and the female gender 45%. The hemorrhage location was sellar/suprasellar in 43% cases. Histopathology of included cases was pilocytic astrocytoma in 41%, followed by pilomyxoid astrocytoma in 16% cases. The outcome was unfavorable; 37.5% cases showed improvement, whereas 18% cases resulted in death.

Conclusion

Apoplexy of the OPHG can be fatal and associated with poor outcomes. A systematic review of the literature has shown that younger age, pilocytic or pilomexyoid astrocytoma histopathology, and chiasmal/hypothalamic locations are associated with a higher risk of intertumoral hemorrhage and poor prognosis. Further genetic studies for OPHG may provide information for high-risk patients.