Teaching File - Gastric Cancer (CT Scan)

Figure: Axial CT shows thickening (arrows) and mucosal enhancement of the lesser curvature of the stomach in a patient with known gastric carcinoma. The fat plane is preserved. No lymphadenopathy is seen.

Gastric Carcinoma

* Etiology: atrophic gastritis, adenomatous polyp, Lynch syndromes, gastric stump cancer, Menetrier's disease
* Usually present in advanced stage
* Major determination of staging of gastric carcinoma = extent of tumor beyond gastric wall and lymph node involvement
* CT usually used to determine presence and extent of perigastric spread

Gastric Carcinoma on CT

* Wall thickening, soft tissue mass (polypoid or ulcerated mass), perigastric fat stranding, lymphadenopathy
* Differentiation from lymphoma: lymphoma usually has a very thick wall, no perigastric stranding, and bulky lymph nodes
* CT accuracy for staging is better with multiplanar reformations (coronal and sagittal), better for T staging than N staging

T Staging by CT

* T1 lesion = focal thickening of the inner layer of the wall
* T2 lesion = transmural thickening of the wall without or with minimal perigastric stranding
* T3 lesion = blurring of at least 1/3 of tumor extent or wide reticular stranding around tumor border
* T4 lesion = invasion of adjancent organ or fat plane obliteration between tumor and adjacent organ
* Accuracy based on this description was 77% in one study, when axial + MPR images were used

Reference:
Hur J, et al. Diagnostic accuracy of multidetector row computed tomography in T- and N staging of gastric adenocarcinoma with histopathologic correlation. J Comput Assist Tomogr 2006 (May/June)