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

BACKGROUND

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.

CASE PRESENTATION

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.

CONCLUSIONS

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.

Anaplastic lymphoma kinase-positive large B-cell lymphoma (ALK + LBCL): a systematic review of clinicopathological features and management

Anaplastic lymphoma kinase-positive (ALK+) large B-cell lymphoma (LBCL) is a rare CD20-negative aggressive lymphoma. Given its rarity, data on ALK + LBCL are scarce and limited to case reports and small case series. Our systematic review included 184 unique cases published in the literature and shows that ALK + LBCL can affect individuals at any age, has a male predominance and is not associated with chronic viral infections. The malignant cells express ALK, VS38c, BLIMP-1, EMA, c-MYC, and BOB-1. The STAT3/STAT5, PI3K/AKT, PLCG2, and ERK pathways are important in the pathophysiology of ALK + LBCL. The prognosis of ALK + LBCL is poor with a 5-year survival rate of 28%. Early disease stage is associated with better outcomes. ALK inhibitors and other targeted agents could be of value in the treatment of ALK + LBCL. Additional research is needed to better understand, diagnose and treat ALK + LBCL.

[CD20-negative diffuse large B-cell lymphoma complicated by rheumatoid arthritis]

CD20 antigen is an important marker for diagnosis of B-cell neoplasms that is highly expressed on the surface of neoplastic B lymphocytes. Patients with rheumatoid arthritis (RA) have an increased risk of developing malignant lymphoma, of which diffuse large B-cell lymphoma (DLBCL) is the most common type. We report an unusual case of CD20-negative DLBCL complicated by rheumatoid arthritis. An 81-year old female presented with a left-sided cervical tumor, enlarged tonsil, and polyarticular pain. Pathological findings of the left tonsil showed proliferation of large atypical cells with irregular shaped nuclei. Most large cells were negative for CD3 and CD20. Additionally, these cells were positive for CD79a, BCL2, and MUM1, and negative for CD10, CD138, BCL6, PAX5, EBV-ISH, HHV8, and ALK.. Therefore, she was diagnosed with CD20-negative DLBCL complicated with RA and received dose-modified CHOP that achieved partial remission. Because CD20-negative DLBCL is rare, the identification of the clinicopathological features of this disease is urgently required.