Background: Multiple early gastric carcinomas were found in 5-15% of patients with early gastric carcinoma. The goals of this study were to clarify the clinicopathologic features of multiple early gastric carcinomas and to investigate their histogenesis.
Methods: Of 724 patients with early gastric carcinoma, there were 65 with multiple (159) gastric carcinomas. Investigation of the histogenesis of multiple gastric carcinomas was conducted using serial sections of the stomach of 33 patients with multiple early gastric carcinomas (MEGC) and 33 patients with solitary early gastric carcinoma (SEGC). The cancerous and epithelial dysplastic lesions were examined by hematoxylin and eosin staining and immunohistochemical staining of p53 protein with anti-p53 monoclonal antibody (BP53-12).
Results: The macroscopically depressed type was common. The flat type was observed only in accessory lesions, most of which were diagnosed postoperatively. There were 126 differentiated type lesions, and 33 poorly differentiated type lesions. In most cases both the main and accessory lesions were differentiated. The average number of epithelial dysplastic lesions (18.3) in the stomach of patients with differentiated MEGC was significantly higher than that in the stomach of patients with differentiated SEGC (7), poorly differentiated MEGC (2.1), and SEGC (2). Moreover, severe dysplastic lesions were frequently observed in the stomach of patients with differentiated MEGC. p53 protein expression was detected in 0.9% of mildly atypical epithelial dysplastic lesions, 3.7% of moderately atypical dysplastic lesions, and 18.2% of severely dysplastic lesions.
Conclusions: In cases of early gastric carcinoma, small depressed type and flat type accessory lesions of multiple gastric carcinomas should be detected preoperatively. Epithelial dysplastic lesions probably are significant in the histogenesis of differentiated multiple gastric carcinomas.