non-Hodgkin’s lymphoma, NHL（3）
2. Follicular lymphoma (follicular lymphoma) Follicular lymphoma is an indolent B-cell tumor derived from cells in the germinal center of lymphoid follicles. It accounts for about 25% to 45% of the NHL in European and American countries or regions, and about 10% of the NHL in my country. It is common in middle-aged people, and there is no gender difference in incidence. Most of the patients are over 40 years old, and they usually show painless swelling of multiple lymph nodes. Inguinal lymph node involvement is common. Enlarged spleen is common. Follicular lymphoma is indolent, with a five-year survival rate of more than 70%.
Pathological changes
The histological feature of follicular lymphoma is that the tumor cells form obvious nodular growth patterns under low power microscope. Tumorous follicles are mainly composed of centrocyte (CC) and centroblast (CB) mixed in different proportions. The nucleus of the central cell has irregular morphology, split grooves, inconspicuous nucleoli, and sparse cytoplasm; the central blast is 2 to 3 times larger than normal lymphocytes or larger, with rounded or lobed nuclei, and small spots of chromatin The masses are distributed close to the nuclear envelope, with one to three nucleoli near the nuclear envelope. These cells renew quickly and represent the proliferative components of tumors. In most follicular lymphomas, the vast majority of tumor cells are central cells. As the course of the disease progresses, the number of central blast cells gradually increases. The growth pattern has developed from follicular to diffuse, suggesting that the malignancy of the tumor is increased.
Immunophenotype and cytogenetics
The tumor cells of follicular lymphoma have the immunophenotype of normal germinal center cells, and the tumor cells express CD19, CD20, CD10 and monoclonal surface immunoglobulins. The tumor cells in most cases also express the bCL-2 protein. This is due to the t(14;18) translocation of the tumor cells, which causes the splicing of the IgH gene on chromosome 14 and the bCL-2 gene on chromosome 18. The bCL-2 gene is highly expressed. Therefore, the bCL-2 protein is also a useful marker for distinguishing reactive hyperplastic follicles from neoplastic follicles of follicular lymphoma.
3. Diffuse large B-cell lymphoma (DLBL) DLBL is a type of aggressive NHL with large morphological changes and heterogeneity, including centroblastic, B-immunoblastic, and intercellular Degenerative large B-cell lymphoma, T-cell/histioblast-rich B-cell lymphoma and plasmablastic lymphoma, etc. The patients are mainly elderly, and men are slightly more common. The tumor not only originated in the lymph nodes, but also originated in the mediastinum, pharyngeal ring, gastrointestinal tract, skin, bone, and brain.
Pathological changes
The histology is characterized by diffuse infiltration of relatively single large cells. The diameter of tumor cells is 4 to 5 times that of small lymphocytes, and the cell morphology is diverse, which can be similar to central blast cells, immunoblast cells, or accompanied by plasma cell differentiation. The cytoplasm is medium, often basophilic, with round or oval nuclei, edged chromatin, and single or multiple nucleoli. There may also be anaplastic multinucleoma giant cells, similar to R-S cells in Hodgkin's disease.
Immunophenotype and cytogenetics
Tumor cells express B cell differentiation antigens CD19 and CD20, and cases transformed from follicular lymphoma also express bCL-2 protein, and t(14;18) can be detected. A small number of cases have bCL-6 gene translocation on chromosome 3.
4. Burkitt lymphoma Burkitt lymphoma is a highly aggressive B-cell tumor that may originate from follicular germinal center cells. Clinically, there are three forms of African regional, sporadic and HIV-related. Latent EB virus infection is closely related to the incidence of Burkitt lymphoma in Africa. It is more common in children and young people. Tumors often occur in the jaws, skulls, facial bones, abdominal organs and central nervous system, forming huge masses.
Pathological changes
The histological characteristics of Burkitt's lymphoma are the diffuse infiltration of medium-sized, relatively single-shaped lymphoid cells. There are scattered macrophages among the tumor cells to phagocytize nuclear debris, forming a so-called starry sky image, with many split images. see. The original lymph node structure is destroyed.
