Ring-Like Nuclear Morphology in Cerebrospinal Fluid Plasma Cells in Central Nervous System Myeloma

multiparameter flow cytometry provide complementary information, with flow cytometry particularly valuable for demonstrating clonality in paucicellular specimens.3 To the best of our knowledge, ring-shaped nuclei have not previously been described in plasma cells from CSF or bone marrow smears in multiple myeloma.The ring-shaped nuclear configuration observed in the CSF plasma cells should be distinguished morphologically from nuclear pseudoinclusions, Dutcher bodies, folded or multilobated nuclei, and signet-ring plasma-cell variants, which exhibit distinct nuclear or cytoplasmic features.4 The biological basis and prognostic significance of this configuration remain unknown.Recognition of this distinctive finding may aid cytological identification of myeloma involvement in CSF and broadens the recognized spectrum of plasma cell morphologic abnormalities in extramedullary disease.The patient received intrathecal chemotherapy combined with oral lenalidomide and dexamethasone, with subsequent improvement in neurological symptoms, and was discharged.