Multiple minute carcinoids in type A gastritis: attempt at 3-D reconstruction

In type A gastritis, the numbers of endocrine cell micronests (ECM) and carcinoids increase through the trophic action of gastrin. This study examined the characteristics and growth of carcinoids in type A gastritis. A total of 395 lesions in five surgically removed stomachs with type A gastritis were investigated, in terms of number, size, distribution and histological appearance, to clarify the tumorigenesis and progression of carcinoids. 3-D reconstruction using serial paraffin sections was used to study carcinoid progression. Our findings suggest that in type A gastritis, carcinoids arise in areas where minute carcinoids are present at a high density. They also suggest that early stage carcinoids not only become large expansively, but also develop in a very complex manner, by maintaining contact with surrounding minute carcinoids.