What is Burkitt Lymphoma?
Burkitt Lymphoma is a highly aggressive form of non-Hodgkin lymphoma that originates from
B lymphocytes. It is characterized by the rapid growth of tumors, primarily affecting the lymph nodes and other tissues of the immune system.
Histological Features
Histologically, Burkitt Lymphoma is identified by a "starry sky" appearance. This distinctive pattern is due to the presence of scattered
macrophages containing phagocytosed apoptotic tumor cells, which appear as clear spaces amidst a background of densely packed malignant cells. The tumor cells are medium-sized with round nuclei, multiple nucleoli, and a high mitotic rate.
Cellular Characteristics
The malignant cells in Burkitt Lymphoma exhibit high proliferative activity, with a high
mitotic index and numerous apoptotic bodies. The cells are usually uniform in size and shape and possess scant cytoplasm. Immunohistochemical staining reveals the expression of B-cell markers such as CD20, CD10, and BCL6, and they are typically negative for TdT (terminal deoxynucleotidyl transferase).
Molecular Pathogenesis
Burkitt Lymphoma is strongly associated with chromosomal translocations involving the
MYC gene on chromosome 8. The most common translocation is t(8;14)(q24;q32), which places the MYC gene under the control of the immunoglobulin heavy chain gene enhancer, leading to its overexpression. This overexpression drives rapid cell proliferation and contributes to the aggressive nature of the disease.
Subtypes
There are three main clinical variants of Burkitt Lymphoma:
1. Endemic (African) Burkitt Lymphoma
2. Sporadic (non-endemic) Burkitt Lymphoma
3. Immunodeficiency-associated Burkitt LymphomaThe endemic form is most commonly seen in children in malaria-endemic regions and is often associated with
Epstein-Barr Virus (EBV) infection. The sporadic form occurs worldwide and affects both children and adults. The immunodeficiency-associated form is seen in patients with HIV/AIDS or other immunocompromised states.
Diagnosis
The diagnosis of Burkitt Lymphoma involves a combination of histological examination, immunophenotyping, and molecular studies. A lymph node biopsy or other tissue biopsy is examined under the microscope to identify the characteristic "starry sky" pattern. Immunohistochemistry is used to determine the expression of B-cell markers and MYC protein. Cytogenetic analysis or fluorescence in situ hybridization (FISH) can detect the MYC gene translocation.Treatment and Prognosis
Burkitt Lymphoma is treated aggressively with a combination of chemotherapy and immunotherapy. The treatment regimens are intensive but can lead to high cure rates, especially in children. The prognosis depends on the stage of the disease at diagnosis, the patient's age, and the presence of other health conditions. Early diagnosis and prompt treatment are crucial for improving outcomes.Conclusion
Burkitt Lymphoma is a fast-growing, aggressive cancer of the B lymphocytes, characterized by its unique histological appearance and association with MYC gene translocations. Understanding its histological and molecular features is essential for accurate diagnosis and effective treatment. With appropriate therapy, many patients with Burkitt Lymphoma can achieve remission and long-term survival.
