Esophageal Gastrointestinal Stromal Tumor With MKRN1-BRAF Fusion: A Rare Mediastinal Case

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal neoplasms typically involving the upper gastrointestinal tract. Most GISTs are driven by activating mutations in the KIT or PDGFRA genes, which are primary molecular markers for diagnosis and treatment. In addition, CD117 and DOG1 (discovered on GIST 1) are important immunohistochemical diagnostic markers of GISTs. Esophageal GISTs are exceptionally rare, and those driven by BRAF gene fusions are even more uncommon. This report describes a 69-year-old woman who underwent surgical resection of an esophageal GIST harboring an MKRN1-BRAF gene fusion, offering insight into future treatment and surveillance strategies.