[Primary central nervous system diffuse large B cell lymphoma: a clinicopathologic and molecular study]

Objective: To investigate clinicopathologic characteristics, immunophenotype and EB virus-related molecular genetic alterations in primary central nervous system diffuse large B cell lymphoma (DLBCL) along with correlation with clinical prognosis. Methods: A total of 30 cases of primary central nervous system DLBCL were retrospectively studied by retrieving clinical data, histological evaluation and immunophenotyping by EnVision two steps methods. The expression of EBER mRNA was detected by in situ hybridization and bcl-2, bcl-6 and C-MYC gene abnormalities were analyzed by interphase fluorescence in situ hybridization. Results: The cases included 18 males and 12 females (sex ratio of 1.5∶1.0) with an age ranging from 24 to 78 years (average age of 52 years, the median age of 53 years). The single primary clinical presentation was focal neurologic deficits. Tumor locations were supratentorial (21 cases), subtentorial (7 cases), involving both locations in 2 cases. Diffuse growth pattern was observed with large lymphoid cells mostly resembling centroblasts with abundant basophilic cytoplasm with oval to round, vesicular nuclei containing fine chromatin. An angiocentric and angiodestructive growth pattern was also present. Other features included perivascular space invasion. Immunohistochemical staining using a panel of CD10, bcl-6 and MUM1, six cases were germinal center-like (GCB) and 24 cases were non-germinal central-like (non-GCB). The positive rates of bcl-2, bcl-6 and C-MYC were 53.3% (16/30), 80.0% (24/30) and 20.0% (6/30), respectively. Genetic alterations were detected by FISH and the gene arrangement rates of bcl-2, bcl-6 and C-MYC were 3.3% (1/30), 16.7% (5/30) and 3.3% (1/30), respectively. There were 19 cases in stage 0-1 disease and 11 cases had stage 2-3 disease. Postoperative follow-up for average 13.6 months showed the median survival of 10 months, one-year survival of 46.7% and 16 patients died within a year. Conclusions: The clinical prognosis of primary central nerve system DLBCL depends on age, clinical performence status score, IPI score, immune classification and treatment. Patients typically progress rapidly with the high mortality within one year of diagnosis. Surgical resection combined with high-dose methotrexate or cytarabine chemotherapy offer the best treatment option.