Coexistence of two lymphomas with distinctive histologic, ultrastructural, and immunologic features.

The unusual coexistence of two distinct lymphomas in 44-year-old woman is described. Nodular, poorly differentiated lymphocytic lymphoma and diffuse histiocytic lymphoma were present in separate sites and were readily distinguished both histologically and ultrastructurally. In addition, the lymphocytic lymphoma was shown to be derived from complement receptor B lymphocytes of follicular center cell type, whereas the histiocytic lymphoma cells were devoid of complement receptors, receptors for IgG (Fc receptors), and surface immunoglobulin. Despite intensive chemotherapy and radiation therapy, the patient died within eight months of the initial diagnosis. Although histiocytic lymphoma was widely disseminated at autopsy, lymphocytic lymphoma was not found. Presumably the histiocytic lymphoma was refractory to therapy, in contrast to the lymphocytic lymphoma, which was selectively eradicated.