The aim of this study is to prospectively collect clinical information of patients with extranodal DLBCL, assess the effectiveness of treatment for extranodal DLBCL in the real world, and explore the optimal treatment strategies in real-world populations.

DLBCL is a highly common aggressive non-Hodgkin's lymphoma. For specific extranodal sites of DLBCL, traditional chemotherapy protocols often cannot provide satisfactory results for patients. The aim of this study is to prospectively collect clinical information of patients with extranodal DLBCL, including the distribution of involved sites (such as central nervous system, testes, skin, breast, gastrointestinal tract, etc.), prognosis of diffuse large B-cell lymphoma with involvement of different extranodal sites, genetic mutation characteristics, correlation with molecular subtypes, impact of different treatment regimens on efficacy, assess the effectiveness of treatment for extranodal DLBCL in the real world, and explore the optimal treatment strategies in real-world populations.

Inclusion Criteria:

• 1. ≥ 18 years (including 18 years).
• 2. Pathologically diagnosed with diffuse large B-cell lymphoma according to the 2016 WHO classification, including non-specific types and various special subtypes.
• 3. Newly diagnosed DLBCL with involvement of extranodal organs.
• 4. Patients who have received clinical treatment for lymphoma.
• 5.Patients with measurable lesions, including at least one effective efficacy assessment.

Exclusion Criteria:

• 1. Patients receiving supportive care only.
• 2. Patients who cannot obtain effective efficacy assessment data.

Adult patients with histologically confirmed diagnosis of non-Hodgkin lymphoma with extranodal involvement or non-Hodgkin lymphoma of rare pathological types attending participating centres.