Fig. 3

Macroscopically, a 2-cm-sized mass in the pancreas head was presented as the resected specimen. Histological examination revealed that the tumor consisted of two cell populations. The white-shaded area indicates a component of well- to moderately differentiated tubular adenocarcinoma cells and the gray-shaded area indicates a component of non-adenocarcinoma cells (a). The adenocarcinoma cells were arranged in an irregular pattern (b). Non-adenocarcinoma cells are arranged in a nest, and the cells had round nuclei, abundant cytoplasm, and coarse chromatin (c). An intermixed central zone exists between the two cell components (d) (asterisk part in Fig. 3a)