[Differential diagnosis of atypical plasma cells in the cerebrospinal fluid]

2102 samples of lumbar cerebrospinal fluid (CSF) were examined by qualitative cytology for atypical plasma cells. Samples from seven patients contained such cells. Retrospective investigation of these patients revealed that four of them had had neuroborreliosis, one had multiple sclerosis, one herpes zoster and one malignant non-Hodgkin lymphoma. It is concluded that in a case of unexplained meningoradiculitis with lymphoplasmocytic reaction in the CSF, morphological analysis of the plasma cells can provide important diagnostic pointers.