A patient with IgM-secreting B-cell lymphoma developed demyelinating peripheral neuropathy, nodular regenerative hyperplasia of the liver, coagulopathy, and terminal miliary lymphomatous spreading. Serologic auto-antibody activities directed against myelin associated glycoprotein, prothrombinase complex (i.e. lupus anticoagulant) and smooth muscle cells were detected. It is suggested that there is a link between the IgM gammopathy, the immunological abnormalities and the various clinico-pathological conditions.