non-Hodgkin’s lymphoma, NHL（4）

Immunophenotype and cytogenetics

The tumor cells of Burkitt's lymphoma are relatively mature B cells, which express monoclonal cell membrane surface immunoglobulins such as sIg, CD19, CD20 and CD10. All Burkitt lymphomas have translocations related to the c-myc gene on chromosome 8. The most common is t(8;14), and t(2;8) or t(8;22) can also occur.

(3) Peripheral T and NK cell tumors

1. Peripheral T-cell lymphoma, unspecific (peripheral T-cell lymphoma, unspecific) is a group of T-cell tumors that are heterogeneous in both morphology and immunophenotype. The WHO classification divides them into one category mainly based on their Clinical behavior. Including the previous classification of T immunoblastic lymphoma, pleomorphic peripheral T cell lymphoma and other subtypes. The patient is often an adult with swollen lymph nodes throughout the body, sometimes with eosinophilia, skin rash, fever, and weight loss. The clinical progress is fast and it is highly invasive.

Although the morphological changes are diverse, the following characteristics are shared by peripheral T-cell lymphomas: lymph node structure destruction, tumors mainly invade the paracortical area, often with vascular proliferation, tumor cells are composed of pleomorphic cells of varying sizes, often accompanied by numerous The non-tumor reactive cells, such as eosinophils, plasma cells, tissue cells, etc.

Tumor cells express mature T cell markers such as CD2, CD3, and CD5. Analysis of gene rearrangements of T cell receptors revealed monoclonal rearrangements.

2. Extranodal natural killer/T-cell lymphoma (extranodal natural killer/T-cell lymphoma) Extranodal NK/T-cell lymphoma is an aggressive tumor derived from cytotoxic cells (cytotoxic T cells or NK cells), most of which occur in Outside the nodal, because the nasal cavity is the most common site for this type of tumor, it is called nasal NK/T cell lymphoma. It is quite common in our country and belongs to EB virus-related lymphoma. The peak age of nasal NK/T cell lymphoma is around the age of 40, and the ratio of male to female is about 4:1. The main lesion is the nasal cavity, followed by the jaw and oropharynx, often involving the nasopharynx and paranasal sinuses.

The histological manifestations of nasal NK/T cell lymphoma are diverse, and the basic pathological changes are that tumor lymphoid cells are scattered or diffusely distributed on the background of coagulative necrosis and mixed infiltration of multiple inflammatory cells. Tumor cells vary in size and morphology. The nucleus is irregular and darkly stained without nucleoli or round or oval. The chromatin edges are concentrated, with one or two small nucleoli. Tumor cells can infiltrate into the blood vessel wall, resulting in lumen stenosis, atresia, and rupture of the elastic membrane, showing a so-called vascular central infiltration.

Tumor cells often express T cell antigen CD2, cytoplasmic CD3, and NK cell marker CD56. In most cases, clonal integration of Epstein-Barr virus DNA and small molecular weight RNA (EBER) encoded by Epstein-Barr virus can be detected.