Primary central nervous system mucosa-associated lymphoid tissue lymphoma: case report and literature review

Primary presentation of intradural non-Hodgkin lymphoma is rare. Recently, B-cell lymphomas of mucosa-associated lymphoid tissue (MALT) have been recognized as an important pathologic subtype. When MALT lymphomas present in the central nervous system (CNS), they are distinguishable from primary high-grade CNS lymphomas. We present the clinicopathologic features of 5 patients with primary CNS MALT lymphoma treated at our institution from 1999 to 2006. Four out of 5 patients were women, and all patients presented with headaches, focal motor deficits, or cranial nerve palsy. Radiologic studies demonstrated ill-defined dural masses in 3 and well-defined masses in 2 patients. Pathology revealed small to medium-sized cells with a moderate amount of cytoplasm and irregular nuclear borders, expressing pan B-cell markers (CD19, CD20, and CD79a) but lacking CD10, CD23, and cyclin D1, confirming low-grade MALT lymphoma. Plasma cells were encountered in all the biopsies with variable reactive T-cell infiltration. wedge chain restriction was seen in 3 patients. Therapy consisted of either surgical resection, whole-brain radiation, or systemic or intrathecal chemotherapy. There was no evidence of recurrence or systemic relapse in 4 patients at 4 years of follow-up. One patient died in 2 months, unrelated to CNS lymphoma. This case series illustrates the rare occurrence of low-grade dural B-cell lymphoma and the need to consider this entity in the differential diagnosis of CNS lesions.