Lymphoma is a malignant neoplastic disease of the hematological system. Lymphoma is divided into Hodgkin’s lymphoma and non-Hodgkin’s lymphoma. Marginal zone B-cell lymphoma belongs to a type of non-Hodgkin’s lymphoma. The marginal zone refers to the structure between the lymphoid follicle and the follicular coat, and lymphomas occurring in this area are mainly of B-cell origin, hence the name marginal zone B-cell lymphoma. It falls under the scope of inert lymphoma and includes lymphoma of the marginal zone of lymph nodes, which mainly occurs in the marginal zone of lymph nodes. In addition, it includes splenic marginal zone B-cell lymphoma, which mainly presents with anemia and enlarged spleen and lymphocytosis. Marginal zone B-cell lymphoma also includes mucosa-associated lymphoid tissue extra-nodal marginal zone lymphoma, which is a lymphoma that occurs in the marginal zone of extra-nodal lymphoid tissue, also known as mucosa-associated lymphoid tissue lymphoma, including Hashimoto’s thyroiditis, and gastric lymphoma associated with Helicobacter pylori, etc.