Primary combined hepatocellular-cholangiocellular sarcoma: An unusual case

Abstract

Primary liver carcinosarcoma is rare. Here we report an unusual case of liver carcinosarcoma containing combined hepatocellular cholangiocarcinoma. A mass in the right liver lobe of a 45-year-old man was accidentally discovered by ultrasonic inspection and computed tomography (CT) scan. Surgical resection was performed following a diagnosis of primary liver cancer. Micropathologically, both carcinomatous and sarcomatous elements were present, and diagnosis of liver carcinosarcoma was confirmed. The carcinomatous element consisted of hepatocellular carcinoma and foci of cholangiocellular carcinoma. The sarcomatous element was composed of spindle cells and bizarre cells, as well as foci of osteosarcoma and chondrosarcoma. Hepatocellular carcinoma cells diffusely expressed both hepatocyte specific markers cytokeratin (CK) 8/18 and cholangiocyte specific markers CK19, and sarcoma cells were positive for vimentin. Interestingly, both carcinomatous and sarcomatous cells expressed epithelial membrane antigen. CD117-positive ductular reactions and small undifferentiated cells were observed. A liver progenitor cell origin of the liver carcinosarcoma was proposed.

Keywords: Carcinosarcoma; Cholangiocellular carcinoma; Hepatocellular carcinoma; Liver neoplasm; Stem cells.

Figure 1

Contrast-enhanced computed tomography showing a 5 cm × 7 cm mass in segments V-VIII of the liver. A: Baseline scan; B: Arterial phase; C: Portal venous phase; D: Delayed phase.

Figure 2

Microscopic appearance of the specimen (hematoxylin and eosin staining). A: Tumor-adjacent liver parenchyma showed portal cirrhosis (magnificaton × 100); B: A transitional zone could be defined between the carcinomatous (lower left) and sarcomatous components (upper right). There were intermingled cells of the two elements (magnificaton × 100); C: Foci of cholangiocellular carcinoma with various grades of differentiation (magnificaton × 100); D: Neoplastic osteoid and chondroid formation was observed in the sarcoma element (magnificaton × 100); E: Metastasis nodule was composed of undifferentiated sarcoma cells with deeply stained nuclei (magnificaton × 40); F: Higher-magnification view of the squared part in panel E.

Figure 3

Immunohistochemical expression of the carcinosarcoma. A: Pan-cytokeratin staining showed diffuse and strong signals for HCC cells; B: HCC elements showed various staining pattern for cytokeratin 19 with intermediate hepatobiliary cell-like tumor cells (arrows); C: Carcinomatous elements were strongly positive for epithelial membrane antigen; D: Spindle cells and chondrosarcoma cells (area fenced by dotted line) were positive for epithelial membrane antigen; E: Carcinoma cells were positive for CD117, as were ductular reactions (arrows) and undifferentiated cells (arrows, inset); F: Sarcoma cells were positive for CD117; G: Sarcomatous elements strongly stained for vimentin; H: Diffuse staining for smooth muscle actin in sarcoma cells; All magnifications are × 100.