Is pathological diagnosis necessary before treatment of lymphoma? A: Pathological diagnosis of lymphoma is necessary before treatment. Because lymphoma is a complex disease, it includes more than fifty different types according to the World Health Organization 2008 4th edition classification of tumors of hematopoietic and lymphoid tissues. Only by performing pathological diagnosis can we accurately classify the type and stage of the disease and ensure that patients receive the most appropriate treatment plan. Compared with other tumors, is the pathological diagnosis of lymphoma very complicated? Is the misdiagnosis rate relatively higher? A: Compared with other solid tumors such as breast cancer, lung cancer and intestinal cancer, the pathological diagnosis of lymphoma is more complicated and the misdiagnosis rate is also relatively high. There are two reasons for this: on the one hand, the typology of lymphoma is complex; on the other hand, the morphology and immunophenotype of lymphoma cells, which are similar to lymphocytes at a certain stage of differentiation, make the diagnosis very difficult. In addition, the differentiation from other malignant tumors, such as undifferentiated carcinoma and hypodifferentiated adenocarcinoma, is also involved in the diagnosis of lymphoma. Is the pathological diagnosis of lymphoma, once wrong, very influential on the subsequent treatment? A: Yes, once the pathological diagnosis of lymphoma is wrong, it will have a great impact on the subsequent treatment. Because different types of lymphoma have different standardized treatment methods or treatment plans, only accurate diagnosis can lead to the correct treatment and the best outcome. As an example, it is known that patients with gastric cancer need to undergo surgery, while lymphomas occurring in the stomach usually do not require surgery. The common mucosa-associated lymphoid tissue extra-nodal marginal zone B-cell lymphoma (also known as MALT lymphoma) can be cured in most cases with a combination of antibiotics to clear H. pylori, while patients with diffuse large B-cell lymphoma need to receive CHOP or R-CHOP regimens of chemotherapy, the two treatment regimens are very different. If MALT lymphoma is misdiagnosed as diffuse large B-cell lymphoma, the patient will be “over-treated”, which not only wastes money but also causes unnecessary harm to the patient mentally and physically.