Non-Hodgkin malignant lymphomas and peripheral neuropathies--13 cases.

Non-Hodgkin's malignant lymphomas (NHML) are malignant lymphoid proliferations which may be of B or T cell type. Thirteen observations of an association between peripheral neuropathy and B type NHML are reported. None of the cases had evidence of meningeal propagation or neurotoxicity from chemotherapy. The NHML were classified according to the Working Formulation and Kiel classifications. The various mechanisms of peripheral neuropathy in these cases were split into four broad groups. Group I consisted of four cases in which the peripheral nerve lesions were directly linked to a propagation of malignant cells into the peripheral nervous system; this was revealed by autopsy and/or nerve biopsy. Malignant B cell proliferation was demonstrated in three out of four of these cases by immunolabelling of the infiltrates. Group II included three patients whose serum contained a monoclonal immunoglobulin (IgM) with antimyelin activity, and two who had pathological IgM deposits in endoneurial connective tissue. Group III comprised two cases. The immune dysfunction of the NHML was responsible for a Guillain-Barré syndrome in one, and for a chronic inflammatory demyelinating polyneuropathy in the other. Group IV included two patients in whom the mechanism of the peripheral neuropathy, although almost certainly directly related to the NHML, could not be determined beyond doubt. The peripheral neuropathy might have been a result of a paraneoplasic process or, possibly, an undetected lymphomatous invasion of nervous tissue. All these cases of clinically diverse peripheral neuropathy, which either occurred before the discovery of the haemopathy or arose as complications of it, are discussed along with similar observations reported in the literature. Immunolabelling of lymphomatous proliferations and nerves is now of considerable value for classifying and indicating the exact aetiology of the peripheral neuropathy. It can also detect pathogenic consequences of any associated monoclonal dysglobulinemia. In any event, a direct link between the peripheral neuropathy and NHML represents an indication for intensification of specific chemotherapy, which in some of our patients led to significant regression of the peripheral neuropathy. Nonetheless, in some cases, the link between peripheral neuropathy and NHML could not be established with certainty. Long-term follow-up is essential in such cases. The present results show the importance of a case by case study of patients with NHML and peripheral neuropathy.