MON-129 Long term efficacy of BRAF and MEK Inhibitors without adjuvant radiotherapy in Residual Papillary Craniopharyngioma: A Case Report

Abstract Disclosure: M. Serebro: None. Y. Greenman: None. D. Limon: None. Background: Craniopharyngiomas are rare intracranial tumors with an annual incidence of 0.16 per 100,000 individuals1. They are histologically categorized into adamantinomatous and papillary subtypes. Traditional management involves surgical resection, but patients with residual disease often require multiple interventions and radiation therapy, leading to significant pituitary dysfunction. The discovery of the BRAF V600E mutation in 95% of papillary craniopharyngiomas2 has introduced BRAF and MEK inhibitors as a novel therapeutic option. Case Presentation: A 34-year-old female presented in 2019 at the age of 29 with severe headaches. Imaging revealed a sellar-suprasellar cystic and solid mass compressing the optic chiasm. She underwent trans sphenoidal resection, confirming a WHO grade 1 papillary craniopharyngioma with BRAF V600E mutation. Postoperative recovery was uneventful, with transient diabetes insipidus resolving spontaneously and intact pituitary function. In April 2020, follow-up imaging showed a rapid growth of the cystic component. She commenced BRAF and MEK inhibitor therapy, resulting in significant tumor reduction. Treatment was complicated by intermittent fever, requiring dose adjustments and sinus surgery. In January 2022, treatment was discontinued after the patient developed neutropenic fever. Despite cessation of therapy, the patient has remained stable with preserved pituitary function and continued tumor reduction on imaging. Conclusion: Emerging evidence3, including a study by Dario De Alcubierre et al., highlights the excellent outcomes achieved by combining BRAF/MEK inhibitor therapy with adjuvant radiotherapy4. Our case illustrates the sustained efficacy of BRAF and MEK inhibitors in managing residual papillary craniopharyngioma, with continued tumor regression observed despite the discontinuation of targeted therapy and the absence of adjuvant radiation therapy. This raises important questions about the necessity of adjuvant radiation therapy in such scenarios. References - 1. Descriptive epidemiology of craniopharyngiomas in the United States. Pituitary (2021) 24:517-522 2. Exome sequencing identifies BRAF mutations in papillary craniopharyngiomas. Nature genetics (2014) 46:161-165 3. BRAF-MEK Inhibition in Newly Diagnosed Papillary Craniopharyngiomas. N Engl J Med (2023) 389:118-26. 4. BRAF and MEK inhibitor targeted therapy in papillary craniopharyngiomas: a cohort study. European Journal of Endocrinology (2024) 191:251-261 Presentation: Monday, July 14, 2025