Abstract: Extra gastrointestinal stromal tumor (EGIST) is a mesenchymal tumor located outside the gastrointestinal tract,with morphological,immunophenotypic,and molecular biology characteristics similar to gastrointestinal stromal tumors.On December 17,2024,the patient underwent a massive tumor resection surgery in the abdominal cavity.Pathological examination revealed a mass in the abdominal cavity,consistent with gastrointestinal stromal tumor (EGIST);The patient recovered well after surgery and was discharged smoothly.Re examination showed no recurrence.At present,surgery is the main treatment for stromal tumors,and postoperative oral imatinib is taken to prevent recurrence.

Key words: abdominal tumor, extragastrointestinal stromal tumor, gastrointestinal stromal tumor, mesentery