Hepatoid carcinoma with serous component of the fallopian tube: a case report with immunohistochemical and ultrastructural studies.

A very rare case of hepatoid carcinoma with serous component arising in the fallopian tube of a 79-year-old woman is presented. The lesion was a 5.0-cm unencapsulated, yellowish-white soft mass. The tumor was composed of hepatoid carcinoma (90%) and serous carcinoma (10%) components. The hepatoid carcinoma was histologically characterized by a proliferation of round to polygonal cells arranged in a trabecular, tubular, sinusoidal, papillary, or solid pattern. The serous component in the fallopian tube also showed in situ lesions. Both components showed an infiltration into the surface of the left ovary, omentum, peritoneum including the pouch of the Douglas, and serosa of the colon. Immunohistochemically, the hepatoid carcinoma was positive for alpha-fetoprotein, polyclonal carcinoembryonic antigen (CEA), hepatocyte paraffin 1, albumin, epithelial membrane antigen, and cytokeratin (CAM5.2). Ultrastructurally, the cytoplasm contained abundant ribosomes, moderate amounts of mitochondria, and rough endoplasmic reticulum that developed into a meshwork and contained mitochondria within it. Microbile channel-like structures and desmosomes were occasionally observed. The association with serous carcinoma indicates mullerian origin rather than germ cell origin. The patient received chemotherapy and was alive without disease at 10 months after surgery.