Collision tumor of hepatocellular carcinoma and neuroendocrine carcinoma involving the liver: Case report and review of the literature

Figure 2 Microscopic findings. A: Moderately differentiated hepatocellular carcinoma (HCC) is found in the upper portion. The malignant cells show a clear and rich cytoplasm. It is separated from neuroendocrine carcinoma (NEC) by a fibrous band. Poorly differentiated NEC is found in the lower portion. The cytoplasm is barely seen, and the N/C (nucleus/cytoplasm) is very high (hematoxylin eosin staining, magnification × 100); B: Immunohistochemical staining of hepatocyte paraffin-1 is positive in the upper HCC portion (magnification × 100); C: Immunohistochemical staining of CD56 is positive in the lower NEC portion (magnification × 100).