CT Characteristics of Signet Ring Cell vs Non-signet Ring Cell Gastric Cancer

Background: While the incidence of gastric cancer has decreased, the incidence of signet-ring cell carcinoma (SRCC) is rising. Patients with advanced SRCC gastric cancer have a worse prognosis and lower chemosensitivity than those with non-signet-ring cell carcinoma (NSRCC). Purpose: To determine the differential radiological features of SRCC from NSRCC gastric cancer on contrast-enhanced computed tomography (CT). Material and Methods: This study included 78 patients with pathologically proven gastric carcinoma, 41 patients with SRCC and 37 patients with NSRCC, diagnosed between January 2010 and December 2019 at Thammasat University Hospital. The demographic and histological characteristics were recorded. CT parameters were independently evaluated by two radiologists, then consensus decisions were reached. Statistically significant CT parameters were identified through the univariate analyses. Results: SRCC tended to occur in younger and female patients. Poorly differentiated tumor histopathology was observed more often in SRCC patients than in NSRCC patients with a statistical difference (P = 0.017). The maximal diameter of the SRCC tumor was significantly greater than NSRCC (P = 0.048). In addition, diffusely infiltrative lesions were more frequently observed in patients with SRCC than in those with NSRCC (P = 0.047). Patients with SRCC tumors tended to present with a layered pattern of contrast-enhancement than in those with NSRCC (P = 0.059). Conclusion: Poorly differentiated tumor histopathology was more frequently observed in SRCC gastric cancer compared with NSRCC. SRCC seemed to occur at a higher frequency in female and younger age patients. CT features of tumor diameter and a diffusely infiltrating lesion were useful for the diagnosis of gastric SRCC.