[Cerebrospinal fluid in benign and malignant monoclonal dysglobulinemias].

The authors compared 9 cases of myeloma and 2 cases of Waldenström's disease with 10 cases of benign monoclonal gammapathies. None of the patients (except one) had neurological involvement; one patient hab diabetes. The study was focused on the immunoglobulins and proteins in the CSF. The following observations were made: - The CSF protein was raised in 8 out of the 11 malignant gammopathies and in 5 out of the 10 benign gammopathies; - An identical monoclonal protein was found in the CSF and serum in all the cases of malignant gammopathies. In the cases considered to be benign, the results were less concordant: one IgM lymphoma had normal CSF; three IgG dysglobulinemias had different immunoglobulins proteins in their CSF: - The mean CSF immunoglobulin level was much higher in the myeloma patients than in the benign gammopathies; - A number of findings suggest intrathecal secretion (at least in the malignant gammopathies). This is also true in a good number of the benign gammopathy cases. Direct tumoural invasion of the CSF may be more common than generally supposed. However, the study of CSF immunoglobulins alone does not establish the diagnosis of malignant dysglobulinemia. Nevertheless, the authors consider that the finding of intrathecal secretion of immunoglobulin, especially in patients with a discordance in FAB and FC fractions, should lead to a closer follow-up of these patients.