Mucinous versus nonmucinous gastric carcinoma: differentiation with helical CT.

PURPOSE

To assess the capability of helical computed tomography (CT) to assist in the differentiation between mucinous and nonmucinous gastric carcinomas, with a focus on the thickened stomach wall itself.

MATERIALS AND METHODS

In 62 patients with pathologically proved mucinous (n = 21) or nonmucinous (n = 41) gastric carcinomas, contrast material-enhanced helical CT images were obtained. The gross appearance, contrast enhancement pattern, predominant thickened layer, and degree of enhancement were retrospectively evaluated. Statistical analyses were performed with Fisher exact, chi(2), and Student t tests. A P value of less than.05 was considered to indicate a statistically significant difference.

RESULTS

The most common type of gross appearance in both carcinomas was fungating: It occurred in 71% of patients with mucinous carcinomas and in 59% of patients with nonmucinous carcinomas. The next most common gross appearance type was ulcerative (24% of patients) in nonmucinous carcinomas and diffusely infiltrative (29% of patients) in mucinous carcinomas (P =.009). The most common contrast enhancement pattern was homogeneous (61% of patients) in nonmucinous carcinomas and layered (62% of patients) in mucinous carcinomas (P =.001). These findings were significantly different. The predominantly affected thickened layer was the high-attenuating inner layer or the entire layer (88% of patients) in nonmucinous carcinomas and the low-attenuating middle or outer layer (57% of patients) in mucinous carcinomas. Only two mucinous tumors showed miliary punctate calcifications in infiltrative lesions.

CONCLUSION

Helical CT may assist in distinguishing mucinous from nonmucinous gastric carcinoma, primarily on the basis of enhancement pattern, predominant layer of the thickened wall, gross appearance, and presence of calcifications.