[Immunochemical diagnosis of hepatic localizations in malignant lymphoid hematologic diseases. Study of 80 cases]

The diagnostic value of immunohistochemistry using monoclonal antibodies was assessed in 100 liver biopsy specimens. The majority of these cases were hepatic localizations of lymphoid malignancies. Ten normal and reactive inflammatory liver biopsies were used as controls. Some monoclonal antibodies directed against leukocyte antigens revealed unexpected reactivities with normal liver structures: biliary tract (anti-CD10, anti-B MB2) and hepatocytes (anti-B LN1). In 12/17 cases of hepatic involvement by large cell malignancy, immunohistochemistry allowed the diagnosis of non Hodgkin's lymphoma (NHL); the remaining 5 cases were metastatic undifferentiated carcinoma. It was difficult to differentiate small cell liver NHL from reactive inflammatory infiltration. New anti-B (MB1, MB2, 4KB5, LN1 and LN2) and anti-T (MT1 and UCHL1) monoclonal antibodies suitable for use on paraffin sections were of value to phenotype NHL when only fixed material was available. But, information was too limited to distinguish malignant from reactive infiltrates. Immunohistochemistry on frozen sections was often necessary to diagnose inflammatory infiltrates and to phenotype NHL. Most NHL were of B cell origin (11/13 cases) and showed monotypic surface immunoglobulins as well as B cell-associated antigens (CD22+). The expression of the T CD5 antigen by B-cell NHL may have some diagnostic value. When monotypic surface immunoglobulins could not be demonstrated (due to background staining) the expression of this antigen by B lymphocytes was considered to be highly indicative of their neoplastic nature. Hairy cell leukemia exhibited a pathognomonic phenotype on frozen sections (CD11c+, CD22+, CD25+). T NHL were rare (2 cases) and difficult to diagnose due to the lack of clonal markers. The diagnosis of Hodgkin's disease in liver (15/20 cases) was facilitated by using paraffin sections of both monoclonal antibodies anti-CD15 (Leu M1) and anti-CD30 (Ber-H2) which detect fixation-resistant antigens expressed by Sternberg cells.