Beyond the GIST: Mesenchymal Tumors of the Stomach

Abstract

Intramural gastric masses arise in the wall of the stomach (generally within the submucosa or muscularis propria), often with intact overlying mucosa. These tumors are typically mesenchymal in origin and have overlapping radiologic appearances. A combination of features such as location, attenuation, enhancement, and growth pattern may suggest one diagnosis over another. Gastrointestinal stromal tumors (GISTs) account for the majority of intramural tumors and can vary widely in appearance, from small intraluminal lesions to exophytic masses that protrude into the peritoneal cavity, commonly with areas of hemorrhage or necrosis. A well-circumscribed mass measuring -70 to -120 HU is a lipoma. Leiomyomas usually manifest as low-attenuation masses at the gastric cardia. Homogeneous attenuation is a noteworthy characteristic of schwannomas, particularly for larger lesions that might otherwise be mistaken for GISTs. A hypervascular mass in the antrum is a common manifestation of glomus tumors. Hemangiomas are also hypervascular but often manifest in childhood. Inflammatory fibroid polyps usually arise as a polypoid mass in the antrum. Inflammatory myofibroblastic tumors are infiltrative neoplasms with a propensity for local recurrence. Plexiform fibromyxomas are rare, usually antral tumors. Carcinoid tumors are epithelial in origin, but often submucosal in location, and therefore should be distinguished from other intramural lesions. Multiple carcinoid tumors are associated with hypergastrinemia, either in the setting of chronic atrophic gastritis or Zollinger-Ellison syndrome. Sporadic solitary carcinoid tumors not associated with hypergastrinemia have a higher rate of metastasis. Histopathologic analysis, including immunohistochemistry, is usually required for diagnosis of intramural masses.

Ulcerated gastric leiomyoma causing massive upper gastrointestinal bleeding: A case report

“…However, it is clinically important to distinguish these two entities, as leiomyomas are benign, while GISTs may display malignant potential (8). True leiomyomas are strongly and diffusely positive for desmin and smooth muscle actin (7).…”

Gastrointestinale Stromatumoren (GIST) – Neues zu Pathologie, Chirurgie und medikamentöser Therapie

“…Die transkutane Punktion unklarer Herde im Bauchraum bei dem Verdacht auf GIST wird aus Grün-den der Zellverschleppung eher zurückhaltend beurteilt. Zur Einordnung mittels bildgebender Verfahren werden insbesondere die Lage, das Kontrastverhalten und das Alter des Patienten herangezogen[27]. Die Entität des extraintestinalen GIST (eGIST) ist fraglich, auch wenn sie immer wieder als eigene Subgruppe mit schlechter Prognose beschrieben wird[28].…”

Laparoscopy-assisted resection of CD117 and CD34 negative gastrointestinal tumor of stomach following tyrosine kinase inhibitor therapy

“…1 CT forms the backbone of diagnosis. 5,6 GISTs can have exophytic, intramural, endoluminal, or combined dumbbellshaped growth pattern. Being subepithelial, most GISTs originate from muscularis propria.…”