Mesenteric gastrointestinal stromal tumor mimicking a pelvic mass - the diagnostic value of vascular pedicle tracing and multiplanar reconstructions: A case report

Abstract

Primary mesenteric gastrointestinal stromal tumors (GISTs), also referred to as extra-gastrointestinal stromal tumors (EGISTs), are rare entities and represent a diagnostic challenge due to their extraintestinal location and predominantly exophytic growth pattern. On imaging, they may mimic pelvic, gynecologic, or retroperitoneal masses, leading to diagnostic delay or inappropriate management. We report the case of a 53-year-old woman presenting with chronic pelvic discomfort, in whom contrast-enhanced computed tomography (CT) revealed a well-circumscribed abdominopelvic mass initially suspected to be of pelvic origin. Careful multiplanar analysis and retrospective tracing of the tumor's vascular pedicle demonstrated arterial supply from a third-order branch of the superior mesenteric artery, suggesting a mesenteric origin. Surgical exploration confirmed a well-encapsulated tumor arising from the small-bowel mesentery, without macroscopic or histological continuity with the bowel wall. Histopathological examination confirmed a low-risk spindle-cell GIST. This case highlights common imaging pitfalls associated with mesenteric GISTs and emphasizes the diagnostic value of vascular pedicle analysis and multiplanar reconstructions in improving preoperative localization and surgical planning.