MALT lymphoma (dura)

Last revised by Frank Gaillard on 12 Mar 2023

MALT lymphomas of the dura (also known as extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue of the dura), are an uncommon form of CNS lymphoma, accounting for an even smaller proportion of dural masses. They are, however, the most common form of primary dural lymphoma, in the vast majority of cases involving cranial dura; spinal involvement is rare 3.

Unlike other CNS lymphomas that are of large B-cell lineage, primary dural lymphomas are related to mucosa-associated lymphoid tissue (MALT), and as a result, have an indolent course and far better prognosis. On imaging, they are difficult to diagnose pre-operatively as primary dural lymphomas share many similarities with meningiomas which are vastly more frequent.

For a discussion of extracranial disease, see MALT lymphoma

MALT lymphomas of the dura are most often encountered in middle-aged individuals, substantially more commonly in females (M:F 1:5-7) 3. They account for < 1% of all CNS lymphoma 1,2

The presentation is usually indolent with symptoms related to mass effect, without features helpful in distinguishing them from meningiomas 1

Unlike other primary CNS lymphomas which are usually of non-Hodgkin B-cell lineage, primary dural lymphomas tend to arise from mucosa-associated lymphoid tissue (MALT), although how and why this is the case so far remains unclear 1 (see MALT lymphoma for a general discussion). It is unclear whether intracranial MALT lymphoma is due to chronic infection/inflammation as is the case in extracranial cases 3.

As is the case with MALT lymphomas elsewhere, these tumors are composed of small rounded lymphocytes, marginal zone cells and plasma cells 2. Occasionally tumor cells are seen extending along perivasular spaces (of Virchow-Robin) 3.

  • positive for CD20, CD79a, BCL2 3

  • negative for CD5, CD10, CD23, BCL6, cyclin D1 3

The vast majority of MALT lymphomas of the dura arise in the intracranial compartment 2

Primary dural lymphoma shares imaging features with other small round blue cell tumors, and other dural masses. These tumors present as an extra-axial lobulated mass, that may be either solitary or multiple and are difficult to distinguish from meningiomas. 

Due to high cellularity, these tumors are typically somewhat hyperdense compared to brain (as are other CNS lymphomas) 1. They generally enhance vividly. 

  • T1: isointense to grey matter

  • T1 C+

    • vivid enhancement (usually homogeneous)

    • brain tumor interface may be indistinct

  • T2

    • iso- to hypointense to grey matter

    • edema common in adjacent brain

  • DWI/ADC: restricted diffusion

Primary dural lymphomas are nonaggressive and patients have excellent outcomes following surgical resection and/or radiation with or without chemotherapy 1-3.

The differential diagnosis is essentially that of other dural masses, including: 

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