Extranodal lymphoma terminating in acute leukemia associated with IgD monoclonal gammopathy. A case report.

A case of malignant lymphoma associated with IgD monoclonal gammopathy is described. Orbital and testicular tumors were observed, while peripheral lymphadenopathy was absent. Neoplastic lymphoid cells appeared in peripheral blood, bone marrow, and pleural effusion with progression of the disease. Analysis of the serum suggested "unreactive" light chain determinants in monoclonal protein. In immunohistochemical studies and in vitro experiments, it was confirmed that IgD monoclonal gammopathy was directly related to the neoplastic cells. These unusual findings suggest that neoplastic changes such as neoplasms of other B-cell systems may occur at various stages in the differentiation and maturation of IgD-forming B-cell lineage.