Two Surgical Cases of Combined Hepatocellular-Cholangiocarcinoma, Intermediate-Cell Subtype: Potentially Characteristic Gross Features

Figure 1

The gross, microscopic, and immunohistochemical examinations of the primary CHC-INT. (a) The cut surface of the first CHC-INT case characteristically shows a poorly demarcated peripheral nodule in lobulated margins, measuring 32 x 21 mm in diameter, which appears clearly whitish in color. Bar = 1 cm. (b) A microscopic examination of the first CHC-INT case (H&E staining) demonstrates an unencapsulated, ill-defined, and expansive nodule (left side), arranged predominantly in a proliferation of solid nests pattern (left side). (c) The first CHC-INT (H&E staining) shows a solid proliferation of atypical epithelial cells, forming trabeculae (left panel) and/or ill-defined, fused tubule-like structures (right panel). These atypical cells are small-to-medium-sized and relatively uniform, having enlarged hyperchromatic nuclei and scant cytoplasm. (d) The cut surface of the second CHC-INT case characteristically reveals a poorly demarcated portal nodule in lobulated margins with central necrosis, measuring 35 x 26 mm in diameter, which appears clearly whitish in color, accompanied by portal vein permeation (arrows). Bar = 1 cm. (e) A microscopic examination of the second unencapsulated CHC-INT tumor (H&E staining) shows a solid proliferation of atypical epithelial cells, arranged predominantly in solid nests, trabeculae, and/or irregular and fused tubule-like structures, aggressively involving the portal vein (right upper side to center) with focal perineural invasion (inset). Left lower side is the intact wall of the portal vein. (f) Immunohistochemistry demonstrates that those second CHC-INT carcinoma cells are specifically positive for not only CK7 (left; cholangiocytes marker) but also CK18 (marker for both hepatocytes and cholangiocytes).

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