Gastrointestinal lymphomas. Immunohistologic study of 23 cases.

Twenty-three primary gastrointestinal lymphomas were studied morphologically and immunologically on fresh frozen tissue, and on cell suspension for 16 of them. Polyclonal antibodies reactive with immunoglobulin chains and a panel of 16 monoclonal antibodies reactive with B- and T-cells, histiocytes, and epithelial cells were used. According to the Working Formulation, 5 cases were low grade, 12 intermediate grade, and 5 high grade; 1 case was an extramedullary plasmocytoma. Forty-seven percent were large cell lymphomas and 13% follicular lymphomas. There were 20 (86%) B-cell lymphomas and 2 T-cell lymphomas; one case lacked detectable markers for B-, T-, or histiocytic cells. Monoclonality was demonstrated in 13 out of the 20 B-cell lymphomas, whereas the other 7 expressed pan-B antigens. It is concluded that immunologic studies on frozen surgical material are of precise diagnostic value in gastrointestinal lymphomas, whereas fixed endoscopic biopsies only permit the distinction between lymphomas and undifferentiated carcinomas.