Isolated B-cell lymphoproliferative disorder at the dura mater with B-cell chronic lymphocytic leukemia immunophenotype.

Lymphoma manifestations of the dura mater are extremely rare and have mostly been attributed to extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) type. We report a patient with an isolated meningeal tumor, identified as a B-cell lymphoproliferative disorder with typical B-cell chronic lymphocytic leukemia immunophenotype. Because of the subclinical detection of trisomy 3 in the bone marrow by cytogenetic analysis and interphase fluorescence in situ hybridization, CD5(+) MALT is an important differential diagnosis; however, to our knowledge, this entity has never been reported in the context of dural lymphoma.