Primary central nervous system CD20-negative diffuse large B-cell lymphoma: a case report

CD20-negative diffuse large B-cell lymphoma is a very rare and heterogeneous invasive cancer characterized by chemical resistance and poor prognosis. Primary CD20-negative diffuse large B-cell lymphoma of the central nervous system is even rarer, presenting great challenges in pathological diagnosis and clinical treatment.

We report a case of primary CD20-negative diffuse large B-cell lymphoma of the CNS in a 54-year-old woman admitted to the hospital with a headache lasting more than 10 days. CT and MRI scans showed right temporal lobe lymphoma. Microscopically, large infiltrating lymphoid cells that induced brain tissue damage were observed. Immunohistochemistry showed that the tumor cells were CD79a⁺, PAX-5⁺, MUM1⁺, and CD20^-. The patient was diagnosed with lymphoma and transferred to an oncology hospital for chemotherapy. However, because the disease progressed rapidly, the patient died only after two rounds of chemotherapy.

To the best of our knowledge, this is one of the first reported cases of unclassifiable CD20-negative diffuse large B-cell lymphoma located in the CNS. This case report aims to deepen the understanding of clinicopathological features of this type of lymphoma and expand the scope of this disease.