INTRODUCTION AND IMPORTANCEGastrointestinal stromal tumors (GISTs) are the most prevalent mesenchymal neoplasms of the gastrointestinal tract, predominantly associated with mutations in the KIT and PDGFRA genes. Neurofibromatosis type 1 (NF1) increases the risk of developing GISTs, particularly in younger individuals, and often presents with atypical features.CASE PRESENTATIONA 16-year-old female with a known diagnosis of NF1 presented with severe anemia, hematemesis, and melena. Physical examination revealed multiple café-au-lait spots and cutaneous nodular masses. A contrast-enhanced CT scan showed a large mass arising from the stomach's greater curvature, consistent with GIST. The patient underwent a sleeve gastrectomy, and histopathological evaluation confirmed high-grade spindle cell GIST. Immunohistochemistry was positive for CD117, CD34, and DOG-1. Postoperative PET-CT showed no residual disease.CLINICAL DISCUSSIONGIST in NF1 patients typically presents with a multifocal pattern, but our patient exhibited a rare unifocal GIST in the stomach. The diagnosis was complicated by atypical presentation and required multimodal imaging and histopathological confirmation. NF1-associated GISTs generally lack KIT and PDGFRA mutations, rendering targeted therapies like imatinib ineffective, emphasizing surgical management as the primary treatment.CONCLUSIONThis case highlights the unique clinical and pathological characteristics of NF1-associated GISTs, stressing the need for vigilant assessment in NF1 patients with gastrointestinal symptoms.