Intracerebral infiltration by monoclonal plasmacytoid cells in Waldenstrom's macroglobulinemia--case report.

A 68-year-old female presented with Waldenstrom's macroglobulinemia with infiltration into the cerebral parenchyma manifesting as increased confusion, memory loss, and disorientation. She had a past history of Waldenstrom's macroglobulinemia treated 3 years before. Magnetic resonance imaging showed a high intensity area on T2-weighted images in the left frontal lobe extending to the corpus callosum which was well enhanced by gadolinium-diethylenetriaminepenta-acetic acid. Direct infiltration of neoplastic cells was confirmed by biopsy. Immunohistochemical examination showed that mature plasmacytoid cells in the cerebral parenchyma were immunoglobulin M and lambda light chain antigen positive, but immature lymphocytes in Virchow-Robin space were negative. Monoclonal proliferation was confirmed by southern blot analysis. She became symptom free and the size of the lesion was dramatically reduced after 40 Gy irradiation. She showed no evidence of recurrence 3 years after irradiation. As no effective chemotherapy regimen for Bing-Neel syndrome has been established, irradiation is worth considering when neuroimaging suggests intracranial infiltration of neoplastic cells.