title: Immunohistological evaluation of single small hepatocellular carcinoma with negative staining of monoclonal antibody Hepatocyte Paraffin 1.
abstract: OBJECTIVE
  The sensitivity and specificity of the monoclonal antibody Hepatocyte Paraffin 1 (Hep Par 1) for hepatocellular carcinoma (HCC) are very high, and the usefulness for differential diagnosis of hepatic tumors has been reported. However, there are some cases of HCC with negative staining for Hep Par 1. We examined the histopathological features of HCC with negative staining for Hep Par 1.
  
  
  METHODS
  We examined 69 samples of single nodular HCC less than 2 cm in greatest dimension, resected from 1985 to 1994 in our hospital, with immunohistological staining for Hep Par 1, cytokeratin 19 (CK 19), MUC-1 glycoprotein (MUC-1), and epithelial membrane antigen (EMA).
  
  
  RESULTS
  Hep Par 1 staining was positive in 64 cases (93%) and negative in 5 cases (7%). With regard to the histological structure, 3 of the 5 negative cases were scirrhous HCC. With regard to the grade of histological differentiation, 2 cases were poorly differentiated HCC, 3 cases were moderately differentiated HCC, and no well-differentiated HCC was found in the negative cases. CK 19, MUC-1, and EMA staining were negative in all cases.
  
  
  CONCLUSIONS
  It is necessary to recognize the existence of Hep Par 1 negative HCC, in particular scirrhous HCC. This may be due to a different mechanism in the earlier stage of hepatocarcinogenesis.
authors.affiliation: Department of Gastroenterological Surgery, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Sugiki
authors.forename: Masakazu
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Atsushi
authors.initials: A
authors.lastname: Aruga
authors.forename: Ken
authors.initials: K
authors.lastname: Takasaki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakano
mesh_terms: D000911:Antibodies, Monoclonal / Q000032:analysis*; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis* / Q000473:pathology; D003594:Cytoplasmic Granules / Q000473:pathology; D003937:Diagnosis, Differential; D022781:Hepatocytes / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012680:Sensitivity and Specificity; D013194:Staining and Labeling
chemical_list: D000911:Antibodies, Monoclonal