Cerebral Metastasis of a Gastrointestinal Stromal Tumor: A Case Report and Literature Review.

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms originating from the gastrointestinal tract. These tumors frequently harbor activating mutations in the receptor tyrosine kinase (KIT) or in the platelet-derived growth factor receptor alpha (PDGFRA) gene, which guide treatment with tyrosine kinase inhibitors (TKIs). Although GISTs commonly metastasize to the liver and peritoneum, involvement of the central nervous system (CNS) is exceptionally uncommon. We report a case of a 58-year-old male with metastatic gastric GIST, treated with imatinib, followed by sunitinib and regorafenib, between October 2021 and December 2023, when he presented with sudden visual disturbances and a transient loss of consciousness. Imaging revealed a large extra-axial lesion in the right frontal region adjacent to a lytic bone lesion. Craniotomy and histopathology confirmed cerebral metastasis from GIST. The patient underwent cranial radiotherapy and was proposed for treatment with ripretinib, but treatment was not initiated due to clinical deterioration. He passed away in March 2024. CNS metastasis from GISTs is a rare phenomenon. Most cases occur in the context of advanced disease and carry a poor prognosis. This case underscores the absence of effective systemic treatments for CNS disease, as most TKIs, including imatinib and ripretinib, have poor CNS penetration. Surgical resection and radiotherapy provide symptomatic relief but are not curative. This case highlights the need for novel therapeutic approaches targeting CNS metastases and further exploration of molecular mechanisms that enable atypical metastatic spread. This report contributes to the sparse literature on CNS involvement in GIST, emphasizing the need for a multidisciplinary approach and the development of therapies that can penetrate the blood-brain barrier (BBB) to improve outcomes in patients with advanced GIST.