Non Hodgkin lymphoma | Pathology and genetics of Non Hodgkin lymphoma | Diagnosis and treatment

Summary

This video provides an in-depth overview of Non-Hodgkin Lymphoma (NHL), a group of cancers affecting lymphocytes, primarily B-cells. The video explains the key differences between Hodgkin and Non-Hodgkin lymphoma, discusses various NHL subtypes like Burkitt, Diffuse Large B-cell, Follicular, and Mantle Cell lymphoma, and highlights their genetic causes. The video also covers B-cell development in the lymph nodes, common symptoms like swollen lymph nodes, and diagnostic methods such as PET scans and biopsies. Lastly, it touches on treatment options including chemotherapy, radiation, and targeted therapies, with plans to explore each subtype in more detail in future videos.

Takeaways

• 😀 Non-Hodgkin Lymphoma (NHL) is a diverse group of lymphoid cancers, primarily involving B-cells, but sometimes T-cells and natural killer cells.
• 😀 NHL accounts for 90% of all lymphoma cases, making it more common than Hodgkin lymphoma, which is rare.
• 😀 Lymphadenopathy (swollen lymph nodes) is the most common symptom of NHL, often seen in the neck, armpit, and groin areas.
• 😀 Non-Hodgkin lymphoma is characterized by the uncontrolled proliferation of lymphocytes (B-cells or T-cells), often due to genetic mutations.
• 😀 There are several subtypes of NHL, including Burkitt lymphoma, Diffuse Large B-cell lymphoma, Follicular lymphoma, Mantle cell lymphoma, and Marginal zone lymphoma.
• 😀 Burkitt lymphoma is associated with chromosomal translocations (8:14), leading to overproduction of a protein that causes uncontrolled cell proliferation, often seen in African children.
• 😀 Diffuse Large B-cell lymphoma is the most common subtype, affecting older adults, with genetic factors like mutations in bcl-2 and bcl-6 contributing to its development.
• 😀 Follicular lymphoma is typically slow-growing and involves the germinal centers of B-cells, often associated with the bcl-2 gene preventing cell death.
• 😀 Mantle cell lymphoma is an aggressive lymphoma caused by the translocation of the cyclin D1 gene, leading to uncontrolled cell cycle progression.
• 😀 Marginal zone lymphoma, although rare, is linked to chronic infections (like H. pylori) and autoimmune diseases, and affects the outer zones of B-cell follicles.
• 😀 Many NHL subtypes are caused by chromosomal translocations that place genes regulating cell division, like bcl-2 and cyclin D1, under the control of strong promoters, leading to unchecked cell proliferation.
• 😀 Diagnosis of NHL is confirmed through imaging (PET scans) to detect areas of high glucose uptake by rapidly dividing cells, and a biopsy is required for definitive identification of the lymphoma type.

Q & A

What is Non-Hodgkin lymphoma (NHL)?

Non-Hodgkin lymphoma (NHL) is a diverse group of lymphoid malignancies, meaning cancers of the lymphocytes (B cells, T cells, or natural killer cells). NHL is primarily characterized by the proliferation of lymphoid cells in lymph nodes and extranodal sites, leading to conditions like lymph node enlargement.

How does Non-Hodgkin lymphoma differ from Hodgkin lymphoma?

The key difference between Non-Hodgkin lymphoma and Hodgkin lymphoma is the absence of Reed-Sternberg cells in NHL, which are characteristic of Hodgkin lymphoma. NHL can involve B cells, T cells, or natural killer cells, whereas Hodgkin lymphoma is primarily associated with B cells.

What is the role of lymph nodes in Non-Hodgkin lymphoma?

Lymph nodes are central to the development of Non-Hodgkin lymphoma, as they are the site where B cells and T cells proliferate abnormally. The enlargement of lymph nodes is a common sign of NHL, indicating an abnormal accumulation of proliferating lymphocytes.

What causes the rapid proliferation of lymphocytes in Non-Hodgkin lymphoma?

The rapid proliferation of lymphocytes in Non-Hodgkin lymphoma is often due to genetic mutations, chromosomal translocations, and overexpression of growth-related genes. These mutations disrupt the normal regulation of lymphocyte survival and division, leading to cancerous growth.

What are some types of Non-Hodgkin lymphoma?

Non-Hodgkin lymphoma includes several subtypes, such as Burkitt lymphoma, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, and marginal zone lymphoma, among others. Each subtype is characterized by distinct genetic and histological features.

What is Burkitt lymphoma, and how is it linked to genetic changes?

Burkitt lymphoma is a highly aggressive B-cell lymphoma often associated with Epstein-Barr virus (EBV) infection. It is caused by a chromosomal translocation between chromosomes 8 and 14, leading to the overproduction of a gene called MYC, which drives uncontrolled cell proliferation.

What is the 'Starry Sky' appearance in Burkitt lymphoma?

The 'Starry Sky' appearance is a distinctive histological feature of Burkitt lymphoma. It refers to a background of densely packed lymphoma cells (the 'sky') interspersed with clear spaces, which are macrophages that have ingested dead cells (the 'stars').

What is the role of BCL2 in follicular lymphoma?

In follicular lymphoma, the BCL2 gene is frequently overexpressed due to a translocation between chromosomes 18 and 14. BCL2 prevents apoptosis (programmed cell death), leading to the survival of B cells that would normally die, thereby causing the slow accumulation of cancerous cells in the lymph nodes.

How is mantle cell lymphoma different from other forms of Non-Hodgkin lymphoma?

Mantle cell lymphoma is an aggressive B-cell lymphoma that arises from the mantle zone of the lymph node. It is characterized by the overproduction of cyclin D1, a protein that regulates cell division. This lymphoma is more common in men and tends to be more aggressive compared to other forms of NHL.

What are the common diagnostic methods for Non-Hodgkin lymphoma?

Diagnostic methods for Non-Hodgkin lymphoma include imaging techniques like PET scans, which detect areas of high glucose uptake (common in rapidly dividing cancer cells), and various biopsy methods, such as excisional, incisional, or bone marrow biopsy, to confirm the presence of lymphoma cells. Molecular testing and immunotyping can also help identify specific genetic markers.