Immunotopographic assessment of lymphoid and plasma cell malignancies in the bone marrow

To determine the utility of tissue section immunochemistry in the evaluation of bone marrow involved by lymphoid and plasma cell malignancies, snap-frozen, undecalcified bone marrow core and aspirate samples from 23 patients with these disorders were studied with a battery of monoclonal antibodies. With techniques that preserve architecture, difficult diagnostic cases characterized by core but not aspirate involvement, or the reverse, were resolved. By means of an extensive battery of monoclonal antibodies applied to serial sections, complex tumor cell phenotypes were established in all 23 cases. In addition to the identification of straghtfoward monoclonal surface immunoglobulin expression in small cleaved cell lymphomas (four cases), the battery approach added immunologic certainty in malignancies with unusual or difficult phenotypes: peripheral T-cell lymphomas with idiosyncratic antigen expression, and chronic lymphocitic leukemias and small cell lymphomas with faint surface immunoglobulin expression (four cases). For the chronic lymphocytic leukemias and the small cell lymphomas, the combined IgD⁺, B²⁺, B¹⁺, Ia⁺, Leu-I⁺ phenotype taken as a whole had greater utility than any isolated marker. The acute lymphocytic leukemias and the myelomas studied demonstrate the wide range of B-cell antigens that must be detected to account for the variety of B-cell neoplasms encountered. Additionally, the previously undescribed phenotypic subset of CALLA⁺ myelomas, which is of prognostic relevance, was indentified. Marrow frozen section immunotyping is a major asset in the evaluation of patients with lymphoma, leukemia, and myeloma when special care is accorded to tissue handling and to treatment of endogenous peroxidase/pseudoperoxidase and interstitial immunoglobulin.