Neutrophil-rich Gastric Carcinoma in the Integrated Cancer Registry of Eastern Sicily, Italy.

Background/Aim: Neutrophil-rich carcinoma is a variant of gastric carcinoma that has not been well-studied or characterized. The purpose of the present study was to reveal the incidence and clinicopathological findings compared to ordinary gastric carcinoma. Patients and Methods: A population-based series of 430 gastric cancers, identified between 2003 and 2006 from the province of Messina (insular Italy; population, 662, 450), was used. The number of tumor-infiltrating neutrophils was assessed in a semi-quantitative manner using the mean value of 20 nonoverlapping high-power fields (magnification, 400; 0.08 mm2). Tumors with >10 neutrophils per 20 high-power fields were arbitrarily considered as neutrophil-rich gastric carcinomas. Moreover, MUC1 immunohistochemical expression was investigated to show possible correlation with neutrophil infiltration in gastric carcinomas. Results: Among 193 gastric cancers resected for curative purposes, 30 (15.54%) were represented by neutrophil-rich gastric carcinomas. These tumors occurred more frequently in patients aged more than 72 years (p<0.05), showing an inverse correlation with mucinous subtype according to the WHO classification (p<0.001) and expressed MUC1. However, intensity and distribution of MUC1 was heterogeneous, and independent of neutrophil infiltration within the tumor stroma. Conclusion: Neutrophil-rich carcinoma seems to represent a distinctive morphological variant of gastric carcinoma, although the true mechanism for the infiltration of neutrophils is still unclear.