Figure 1

Representative images of acinar-type carcinomas in our series. (a, b) Pure acinar cell carcinomas revealed several different architectural patterns: (a) the solid pattern; (b) the acinar; (c) one of the four hepatic primary cases; (d) acinar differentiation was confirmed with trypsin immunohistochemical staining for each case; (e) the vast majority of mixed acinar neuroendocrine carcinomas were composed of a morphologically homogenous population of cells and the divergent differentiation could not be detected without immunohistochemical labeling. However, in some cases, there were two distinct populations of neoplastic cells, one with acinar features and the other having a neuroendocrine appearance as shown here; (f) in mixed acinar ductal carcinomas, glandular structures were also usually superimposed on the solid architecture of conventional acinar cell carcinomas.