Primary Dural Diffuse Large B-Cell Lymphoma: A Report of a Rare Case and Review of the Literature.

Primary dural lymphoma (PDL) is a rare subtype of primary central nervous system lymphoma (PCNSL), accounting for fewer than 1% of cases. It originates from the dura mater with no evidence of parenchymal or systemic involvement and is usually a low-grade marginal zone B-cell lymphoma (MZL). High-grade variants, including diffuse large B-cell lymphoma (DLBCL), are extremely uncommon and clinically more aggressive. We describe the case of a 65-year-old immunocompetent man who presented with progressive headaches and right-sided weakness. Brain MRI revealed a right frontoparietal dural-based enhancing lesion with a dural tail, closely mimicking meningioma on imaging. Subtotal resection was performed, and histopathology showed large atypical B cells positive for CD20, CD79a, CD10, and BCL6, with a Ki-67 index greater than 60%, confirming a diagnosis of primary dural DLBCL. The patient received six cycles of rituximab-based chemotherapy (R-CHOP: rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone), followed by cranial radiotherapy, and achieved complete remission after 12 months. PDL often imitates meningioma on imaging, which may lead to diagnostic delays. While MZL subtypes typically behave indolently, DLBCL variants require aggressive multimodal therapy. This report highlights the importance of histopathologic confirmation in all dural-based lesions and demonstrates that early multidisciplinary management, including surgery, rituximab-based chemotherapy, and radiotherapy, can result in sustained remission even in highly aggressive forms.