Anaplastic large cell lymphoma (ALCL) is a rare subtype of non-Hodgkin's lymphoma (NHL), a group of blood cancers that affect while blood cells called lymphocytes. With NHL, the lymphocytes grow out of control. These cells are a part of the immune system which helps protect your body from germs and diseases. There are two main types of lymphocytes - B lymphocytes and T lymphocytes. With ALCL, the T lymphocytes are the cells that grow out of control.
Anaplastic Large Cell Lymphoma Means:
- Anaplastic: This term is used to describe abnormal-looking cancer cells. When you look at ALCL cells under a microscope, the look different compared to healthy T lymphocytes.
- Large cell: When viewed under a microscope, the abnormal-looking, cancerous T lymphocytes appear larger than normal T lymphocytes.
- Lymphoma: Lymphoma is a type of blood cancer where white blood cells called lymphocytes grow out of control. ALCL arises from the abnormal growth of T lymphocytes.
ALCL is specifically characterized by large, abnormal lymphocytes that may be found in the lymph nodes or in other parts of the body including the skin, soft tissue, lungs, or liver.
Anaplastic Large Cell Lymphoma Can Be Separated Into Four Different Subtypes
- ALK-positive ALCL: an aggressive type of ALCL where a portion of the ALK gene has merged with another site on the same or different chromosome to form a gene that overproduces a fusion protein called anaplastic lymphoma kinase (ALK). ALK-positive ALCL is typically more responsive to standard chemotherapy regimens and has a better prognosis compared to ALK-negative ALCL.
- ALK-negative ALCL: an aggressive type of ALCL that lacks changes to the ALK gene and generally has a less favorable outcome than ALK-positive ALCL.
- Primary cutaneous ALCL: a rare type of slow-growing ALCL that presents on the skin and very rarely involves surrounding lymph nodes. The characteristic features of this subtype are single or multple raised red skin lesions, nodules or tumors. This subtype generally has good outcomes and is negative for ALK changes.
- Breast implant-associated ALCL: a unique subtype of ALCL that forms around breast implants and is usually diagnosed about 10 years following a breast augmentation or breast reconstruction procedure.
Who Gets Anaplastic Large Cell Lymphoma?
ALCL is a rare type of non-Hodgkin's lymphoma. ALCL comprises about 2.5% of all non-Hodgkin's lymphomas and approximately 16% of all T cell lymphomas. Roughly 1,500 cases are diagnosed annually in the United States. The different subtypes of ALCL affect different groups of people.
- ALK-positive ALCL: Most common in children and young adults in their 30s. It affects three times more males than females
- ALK-negative ALCL: Most common in older adults, typically around 40 to 65 years old. It is slightly more common in men than women
- Primary cutaneous ALCL: Most common in adults ages 50 to 70 and affects men more often than women
- Breast implant-associated ALCL: Most common in people with breast implants that have a rough, textured surface
Why Do People Get Anaplastic Large Cell Lymphoma?
The exact cause of ALCL is unknown, but it is thought to result from genetic mutations that cause lymphocytes to grow and divide uncontrollably. It is not a hereditary disease and is not contagious. Infection with the Epstein-Barr virus (EBV) has been associated with the development of lymphoma. EBV is a common virus that can infect B cells and T cells, and it may play a role in the transformation of these cells into cancerous lymphoma cells. Additionally, some studies have suggested potential associations between certain environmental or occupational exposures and an increased risk of ALCL but no particular agents have been clearly identified to be culprits. Individuals who have HIV and those who have undergone a stem cell or solid organ transplant may be at higher risk.
It's important to note that ALCL is a rare lymphoma, and most people with the risk factors mentioned above do not develop the disease. Additionally, ongoing research is needed to better understand the underlying causes and risk factors associated with ALCL.