Cutaneous T-cell Lymphomas

Cutaneous T-cell lymphomas (CTCL) are a rare, persistent, very slow-growing type of non-Hodgkin lymphoma, a cancer of a type of white blood cell called lymphocytes.

Lymphomas (see also Overview of Lymphoma) are cancers of a specific type of white blood cells known as lymphocytes. These cells help fight infections. Lymphomas can develop from either of the 2 main types of lymphocyte:

• B lymphocytes

• T lymphocytes

B lymphocytes produce antibodies, which are essential in fighting off some infections. T lymphocytes are important in regulating the immune system and in fighting viral infections.

The most common types of CTCL are

• Mycosis fungoides

• Sézary syndrome

Most people who develop CTCL are older than 50 years. It originates from mature T cells (T lymphocytes) and first affects the skin.

Mycosis fungoides starts so subtly and grows so slowly that it may not be noticed initially. It causes a long-lasting, itchy rash—sometimes a small area of thickened, itchy skin that later develops nodules and slowly spreads. In some people, it develops into a form of leukemia. In other people, it progresses to the lymph nodes and internal organs. Even with a biopsy, doctors have trouble diagnosing this disease in its early stages. However, later in the course of the disease, a biopsy shows lymphoma cells in the skin.

Mycosis Fungoides

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DR P. MARAZZI/SCIENCE PHOTO LIBRARY

Sézary syndrome also starts subtly and grows slowly. It causes the skin to become red all over the body with cracking of the palms and soles. In people with dark skin, the redness may be subtle and hard to detect. Lymph node enlargement is usually mild. In addition to the rash, people may also have symptoms of fever, night sweats, and weight loss. As with mycosis fungoides, doctors have trouble diagnosing this disease in its early stage even with a skin biopsy. A blood smear (where a drop of blood is examined under a microscope) may show Sézary cells (malignant T cells with a characteristic appearance) and this can help make the diagnosis in addition to a skin biopsy.

Treatment of CTCL can be divided into

• Therapy directed at the skin, such as light therapy (phototherapy) or topical medications

• Bodywide therapy, such as chemotherapy or targeted medications, usually given intravenously

Therapy directed at the skin is usually started first and is often effective for years. This type of treatment includes medicated creams such as corticosteroids or retinoids applied to the skin, a form of radiation therapy called electron beam therapy, or sunlight (phototherapy).

Chemotherapy is given if skin-directed therapy has failed or in people with CTCL that has spread beyond the skin.