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, X², 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.