GISTs are typically submucosal tumors, and the overlying mucosa often remains intact on pathological and imaging assessment. They are believed to arise from the interstitial cells of Cajal 2,3 or their precursors; 95% stain positive for CD117 (c-KIT) and 70% for CD34 2.

Exophytic gastric mass with CT and MR features highly suggestive of a GIST. Histopathology: spindle cell tumor, formed of interdigitating bundles of atypical spindle cells, having irregular nuclei with low mitotic figures.

Gastrointestinal stromal tumor (GIST) is a rare tumor originating in the digestive tract, often in the stomach or small intestine. It can vary in aggressiveness and requires specialized treatment, such as surgery or targeted therapy, based on its size, location, and genetic characteristics.

Interpretation: Based on the imaging features, a large gastrointestinal stromal tumor is high on the differential list. Gastric lymphoma thought less likely given the lack of associated lymph node enlargement.

A rare mitotic figure is identified. Lesional cells immunoreactive with antibodies against CD117 (c-kit) and SMA and are negative with antibodies against desmin. Ki67 proliferative index is < 3%. Conclusion: Subepithelial D2 lesion biopsy: Gastrointestinal stromal tumor (GIST).

CT and surgical resection were later performed. Pathology Macroscopic: tumor with superficial ulcerations; microscopic morphologic type- epithelioid cells, low mitotic count- >5/50 HPF Immunohistochemistry: tumor cells show positive (+) c-kit and negative (-) S100, CD34, SMA reaction. Conclusion: gastrointestinal stromal tumor.

Typical imaging features of a gastric GIST, which, on CT was not entirely convincing to not have pancreatic involvement. Further workup with MRI showed the lesion to be confined to the gastric wall.

Rectal GIST is rare involving about 5% of cases. Radiological features of GIST are: a well demarcated margins, prominent extraluminal location, no surrounding lymphadenopathy and lack of bowel lumen constriction.

MRI features of a submucosal tumor of the stomach suggestive of a gastrointestinal stromal tumor (GIST). The main differential diagnosis includes the other gastrointestinal tumors:

What are some typical gastrointestinal stromal tumor (GIST) characteristics? Gastrointestinal stromal tumours (GISTs) are a biologically distinctive tumour type of the gastrointestinal tract (GIT), differing from smooth muscle and neural tumours.