title: Hepatoid variant of yolk sac tumor of the testis.
abstract: A case of testicular yolk sac tumor (endodermal sinus tumor) consisting predominantly of hepatoid cells is documented. A mass measuring approximately 4 x 3 cm was noted in the left testis of a 64-year-old man. Preoperative examination revealed an elevated serum level of alpha-fetoprotein (5479 ng/mL). Histologically, the lesion was composed predominantly of sheet-like or trabecular proliferation of hepatocyte-like cells with eosinophilic or clear cytoplasm. The tumor cells were immunoreactive for alpha-fetoprotein, antimitochondrial antibody, cytokeratin (AE1/AE3), alpha-1-antichymotrypsin, alpha-1-antitrypsin, albumin, carcinoembryonic antigen and epithelial membrane antigen. It was necessary to distinguish this variant lesion from metastatic hepatocellular carcinoma, embryonal carcinoma and hepatoid carcinoma.
authors.affiliation: Department of Pathology, Tottori University Hospital, Yonago, Japan. yhorie-ttr@umin.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Horie
authors.forename: M
authors.initials: M
authors.lastname: Kato
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis; D018236:Carcinoma, Embryonal / Q000175:diagnosis; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis / Q000556:secondary; D003937:Diagnosis, Differential; D018240:Endodermal Sinus Tumor / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D022781:Hepatocytes / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis; D013736:Testicular Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D000509:alpha-Fetoproteins