Primary Dural Based Marginal Zone B-Cell Lymphoma Presenting as Focal Dura Thickness with Pachymeningeal Enhancement

摘要

Background and Purpose: Primary Dural Based Marginal Zone B-Cell Lymphoma (MZBCL) is a subtype of primary lymphomas of the CNS (PCNSL) with an incidence rate ranging from 0.6 to 3% of all brain tumors. MZBCL typically presents as an extra-axial mass resembling meningioma. Here we report an unusual case of MZBCL with initial radiographic findings of mild nonspecific thickening tentorium and pachymeningeal enhancement surrounding 7th and 8th cranial nerves. Methods and Results: A 58-year old woman with clinical history of cytomegalovirus infection, polyclonal gammopathy and unruptured left internal carotid artery aneurysm post coil embolization who presented for an evaluation of mild thickening and enhancement of the left tentorium cerebelli and 7th/8th nerve root complex. Differential considerations included inflammatory/autoimmune conditions (idiopathic hyper-trophic pachymeningitis, neurosarcoidosis, Tolosa-Hunt syndrome), infections, structural lesion, benign or malignant neoplasm. Serum studies were normal. Multiple CSF studies were negative. Flow cytom-etry showed no malignant cells with few small lymphocytes. She was followed with the imaging surveillance for nine months until further increased thickening of dura on MRI. She underwent cerebel-lar dural biopsy that was consistent with MZBCL composed mainly of small CD20+ B-cells and negative MYD88. PET scan showed no systemic involvement. Bone biopsy revealed no evidence of lymphoma. The focal leptomeningeal enhancement improved significantly after she received four doses of systemic rituximab treatments. Conclusion: Our case highlights the importance of surveillance and brain biopsy in cases of mild focal dura/pachymeningeal thickness and enhancement if no conclusive diagnosis has been established, as it might be one of the rare tumors such as MZBLC.