Case report: Primary intracranial mucosa-associated lymphoid tissue lymphoma presenting as two primary tumors involving the cavernous sinus and extra-axial dura, respectively

Abstract

Primary intracranial mucosa-associated lymphoid tissue (MALT) lymphoma is a rare type of brain tumor, with only a few reported cases worldwide that mostly have only one lesion with conventional magnetic resonance imaging (MRI) findings. Here, we present a special case of intracranial MALT lymphoma with two mass lesions radiographically consistent with meningiomas on MRI before the operation. A 66-year-old woman was admitted to the hospital with intermittent right facial pain for 1 year, aggravated for the last month. Brain MRI showed two extracerebral solid masses with similar MR signal intensity. One mass was crescent-shaped beneath the skull, and the other was in the cavernous sinus area. Lesions showed isointensity on T1WI and T2WI and an intense homogeneous enhancement after contrast agent injection. Both lesions showed hyperintensity in amide proton transfer-weighted images. The two masses were all surgically resected. The postoperative pathology indicated extranodal marginal zone B-cell lymphoma of MALT. To improve awareness of intracranial MALT lymphoma in the differential diagnosis of extra-axial lesions among clinicians, we present this report and briefly summarize previously reported cases to describe the clinical, pathological, radiological, and treatment features.

Keywords: central nervous system; extranodal marginal zone lymphoma; magnetic resonance imaging; mucosa-associated lymphoid tissue; primary intracranial tumor; treatment.

Figure 1

Axial T1WI (A) and T2WI (B) show a fusiform lesion isointensity to gray matter in the right cavernous sinus (CS). T1WI (D) and T2WI (E) show a crescent–shaped extra–axial mass in the right fronto–temporo–parietal region dura. The right CS lesion (J) extends into the posterior cranial fossa into the internal auditory canal and encircles the auditory nerve and facial nerve (K). Post–contrast T1–weighted (C, F, G, H, I) images show intense homogeneous enhancement of the mass lesions with both dural tails visible. The leptomeningeal involvement of the right extra–axial dura lesion shows serrated enhancement on contrast–enhanced T2–FLAIR (L). APTw image (M) shows a relative homogeneous tumor mass, with APTw signal intensity rates of 2.2%–4.3% (mean: 3.1%).

Figure 2

Microscopic examination shows a diffuse infiltrate of lymphocytes, plasma cells, and some cells with intermediate lymphoplasmacytic morphology (A). The lymphocytic infiltrates were positive for CD20 (B), CD21 (C), and CD79a (D). These lymphocytes and plasma cells are monotypic for kappa light chain (E) expression, and they are essentially negative for lambda light chain (F).

Figure 3

Axial T1WI (A), T2WI (B), and T2–FLAIR (C) demonstrate postoperative alterations in CS. In axial T1WI (D), T2WI (E), and T2–FLAIR (F) images, an obvious edema zone can be seen in the right parietal frontal brain, which may be related to brain changes after radiotherapy. No tumor recurrence was found in post–contrast T1–weighted (G–L) images.