To explore the pathological diagnostic features of primary central nervous system diffuse large B-cell lymphoma (CNS DLBCL).

The clinical data of 15 cases of CNS DLBCL confirmed by Pathology Department in Taian Central Hospital from January 2010 to December 2015 were retrospectively analyzed. Pathomorphological characteristics and immunophenotype of CNS DLBCL were summarized.

Among the 15 patients, 10 cases were male and 5 cases were female. Their ages at the time of operation ranged from 52 to 64 years. The clinical manifestations of 15 cases were headache, dizziness, slow response or unsteady walking. CT examinations showed intracranial space occupying in all patients. Four cases had metastasis, and spread to testis, liver, lung and breast, respectively. Positron emission computed tomography (PET-CT) of other 11 cases showed no metastasis. Under light microscope, tumor cells showed diffuse growth and characterized by their distribution in the perivascular space. Most tumor cells were similar to central mother cells, and were mixed with reactive small lymphocytes, macrophages, activated microglia and reactive astrocytes.Immunohistochemistry showed that cluster of differentiation 20 (CD20) and B cell-specific activator protein (PAX5) were strongly diffused in tumor cells, among which 3 cases expressed CD10, 7 cases expressed B cell lymphoma 6 (Bcl-6) and multiple myeloma oncogene 1 (MUM1), and the remaining 5 cases expressed MUM1. Proliferation cell nuclear antigen (Ki-67) index was 70%-90%.

CNS DLBCL is a relatively rare form of lymphoma. It is characterized by diffuse growth of central mother cell-like cells distributed in the perivascular space. The clinical manifestation is related to the site of occurrence. Thorough understanding of the associated clinical features and immunohistochemic results is helpful in achieving at the correct diagnosis.