E1093. Multimodality Imaging of Mesenchymal Lesions of the Gastrointestinal Tract
  1. Kenneth Huynh; Mayo Clinic - Scottsdale
  2. Ba Nguyen; Mayo Clinic - Scottsdale
Soft tissue mesenchymal lesions are ubiquitously found throughout the body but rarely occur distinctively in the gastrointestinal (GI) tract. Gastrointestinal stromal tumors (GIST) account for 90% of GI mesenchymal lesions, however only comprise of less than 1% of overall GI tract tumors. Less common mesenchymal lesions range from benign schwannoma, leiomyoma, inflammatory fibroid polyp (IFP), granular cell tumor, and gangliocytic paraganglioma to malignant lesions such as leiomyosarcoma, clear cell sarcoma, inflammatory myofibroblastic tumor (IMT), and primary GI melanoma. Radiologic appearances and characteristics of these lesions commonly overlap and lead to broad differential diagnosis. Accurate diagnosis is crucial as otherwise treatable lesions with malignant potential may be mistaken for a benign process. A multimodal approach including PET/CT and attention to unique imaging characteristics may aid in narrowing the diagnosis.

Educational Goals / Teaching Points
1. To review the common and uncommon mesenchymal lesions of the GI tract with histopathologic findings, differential diagnosis, and prognosis. 2. To characterize imaging features of each GI tract mesenchymal lesion to narrow diagnostic possibilities using CT, MR, PET/CT, and ultrasound. 3. To propose a simplified radiological approach to differential diagnosis of a GI tract mesenchymal lesion.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
This exhibit will present imaging features of GI tract mesenchymal lesion on CT, MR, PET/CT, and ultrasound. These lesions include GIST, schwannomas, perineurioma, leiomyomas, leiomyosarcomas, IFP, IMT, granular cell tumors, gangliocytic paragangliomas, clear cell sarcomas, mesenteric fibromatosis, sclerosing mesenteritis, ganglioneuromas, glomus tumors, calcifying fibrous tumors, and primary GI melanomas. This exhibit will also review typical locations of occurrence along the GI tract and discuss a simplified approach to aid in their differential diagnosis.

The viewer will be familiar with common and uncommon GI tract mesenchymal lesions and be able to differentiate between the different lesions through a combination of imaging features using multimodality imaging.