Mycosis fungoides and Sézary syndrome are diseases in which lymphocytes (a type of white blood cell) become malignant (cancerous) and affect the skin.

Normally, the bone marrow makes blood stem cells (immature cells) that become mature blood stem cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell. A myeloid stem cell becomes a red blood cell, white blood cell, or platelet. A lymphoid stem cell becomes a lymphoblast and then one of three types of lymphocytes (white blood cells):

• B-cell lymphocytes that make antibodies to help fight infection.
• T-cell lymphocytes that help B-lymphocytes make the antibodies that help fight infection.
• Natural killer cells that attack cancer cells and viruses.

In mycosis fungoides, T-cell lymphocytes become cancerous and affect the skin. When these lymphocytes occur in the blood, they are called Sézary cells. In Sézary syndrome, cancerous T-cell lymphocytes affect the skin and large numbers of Sézary cells are found in the blood.

Mycosis fungoides and Sézary syndrome are types of cutaneous T-cell lymphoma.

Mycosis fungoides and Sézary syndrome are the two most common types of cutaneous T-cell lymphoma (a type of non-Hodgkin lymphoma).

Mycosis fungoides is the most common form of a type of blood cancer called cutaneous T-cell lymphoma. Cutaneous T-cell lymphomas occur when certain white blood cells, called T cells, become cancerous; these cancers characteristically affect the skin, causing different types of skin lesions. Although the skin is involved, the skin cells themselves are not cancerous. Mycosis fungoides usually occurs in adults over age 50, although affected children have been identified.

Mycosis fungoides may progress slowly through several stages, although not all people with the condition progress through all stages. Most affected individuals initially develop skin lesions called patches, which are flat, scaly, pink or red areas on the skin that can be itchy. Cancerous T cells, which cause the formation of patches, are found in these lesions. The skin cells themselves are not cancerous; the skin problems result when cancerous T cells move from the blood into the skin. Patches are most commonly found on the lower abdomen, upper thighs, buttocks, and breasts. They can disappear and reappear or remain stable over time. In some affected individuals, patches progress to plaques, the next stage of mycosis fungoides.

Plaques are raised lesions that are usually reddish, purplish, or brownish in color and itchy. Plaques commonly occur in the same body regions as patches. While some plaques arise from patches, others develop on their own, and an affected person can have both patches and plaques simultaneously. As with patches, cancerous T cells are found in plaques. Plaques can remain stable or can develop into tumors. Not everyone with patches or plaques develops tumors.

The tumors in mycosis fungoides, which are composed of cancerous T cells, are raised nodules that are thicker and deeper than plaques. They can arise from patches or plaques or occur on their own. Mycosis fungoides was so named because the tumors can resemble mushrooms, a type of fungus. Common locations for tumor development include the upper thighs and groin, breasts, armpits, and the crook of the elbow. Open sores may develop on the tumors, often leading to infection.

Although rare, the cancerous T cells can spread to other organs, including the lymph nodes, spleen, liver, and lungs. Spread to other organs can occur in any stage of mycosis fungoides but is most common in the tumor stage. In addition, affected individuals have an increased risk of developing another lymphoma or other type of cancer.

Sézary syndrome is an aggressive form of a type of blood cancer called cutaneous T-cell lymphoma. Cutaneous T-cell lymphomas occur when certain white blood cells, called T cells, become cancerous; these cancers characteristically affect the skin, causing different types of skin lesions. In Sézary syndrome, the cancerous T cells, called Sézary cells, are present in the blood, skin, and lymph nodes. A characteristic of Sézary cells is an abnormally shaped nucleus, described as cerebriform.

People with Sézary syndrome develop a red, severely itchy rash (erythroderma) that covers large portions of their body. Sézary cells are found in the rash. However, the skin cells themselves are not cancerous; the skin problems result when Sézary cells move from the blood into the skin. People with Sézary syndrome also have enlarged lymph nodes (lymphadenopathy). Other common signs and symptoms of this condition include hair loss (alopecia), skin swelling (edema), thickened skin on the palms of the hands and soles of the feet (palmoplantar keratoderma), abnormalities of the fingernails and toenails, and lower eyelids that turn outward (ectropion). Some people with Sézary syndrome are less able to control their body temperature than people without the condition.

The cancerous T cells can spread to other organs in the body, including the lymph nodes, liver, spleen, and bone marrow. In addition, affected individuals have an increased risk of developing another lymphoma or other type of cancer.

Sézary syndrome most often occurs in adults over age 60 and usually progresses rapidly; historically, affected individuals survived an average of 2 to 4 years after development of the condition, although survival has improved with newer treatments.

Although Sézary syndrome is sometimes referred to as a variant of another cutaneous T-cell lymphoma called mycosis fungoides, these two cancers are generally considered separate conditions.

The cause of mycosis fungoides is unknown. Most affected individuals have one or more chromosomal abnormalities, such as the loss or gain of genetic material. These abnormalities occur during a person's lifetime and are found only in the DNA of cancerous cells. Abnormalities have been found on most chromosomes, but some regions are more commonly affected than others. People with this condition tend to have additions of DNA in regions of chromosomes 7 and 17 or loss of DNA from regions of chromosomes 9 and 10. It is unclear whether these genetic changes play a role in mycosis fungoides, although the tendency to acquire chromosome abnormalities (chromosomal instability) is a feature of many cancers. It can lead to genetic changes that allow cells to grow and divide uncontrollably.

Other research suggests that certain variants of HLA class II genes are associated with mycosis fungoides. HLA genes help the immune system distinguish the body's own proteins from proteins made by foreign invaders (such as viruses and bacteria). Each HLA gene has many different normal variations, allowing each person's immune system to react to a wide range of foreign proteins. The specific variants are inherited through families. Certain variations of HLA genes may affect the risk of developing mycosis fungoides or may impact progression of the disorder.

It is possible that other factors, such as environmental exposure or certain bacterial or viral infections, are involved in the development of mycosis fungoides. However, the influence of genetic and environmental factors on the development of this complex disorder remains unclear.

A sign of mycosis fungoides is a red rash on the skin.

Mycosis fungoides may go through the following phases:

• Premycotic phase: A scaly, red rash in areas of the body that usually are not exposed to the sun. This rash does not cause symptoms and may last for months or years. It is hard to diagnose the rash as mycosis fungoides during this phase.
• Patch phase: Thin, reddened, eczema-like rash.
• Plaque phase: Small raised bumps (papules) or hardened lesions on the skin, which may be reddened.
• Tumor phase: Tumors form on the skin. These tumors may develop ulcers and the skin may get infected.

Check with your doctor if you have any of these signs.

In Sézary syndrome, cancerous T-cells are found in the blood.

Also, skin all over the body is reddened, itchy, peeling, and painful. There may also be patches, plaques, or tumors on the skin. It is not known if Sézary syndrome is an advanced form of mycosis fungoides or a separate disease.

Tests that examine the skin and blood are used to diagnose mycosis fungoides and Sézary syndrome.

The following tests and procedures may be used:

• Physical exam and health history: An exam of the body to check general signs of health, including checking for signs of disease, such as lumps, the number and type of skin lesions, or anything else that seems unusual. Pictures of the skin and a history of the patient’s health habits and past illnesses and treatments will also be taken.
• Complete blood count with differential: A procedure in which a sample of blood is drawn and checked for the following:
  • The number of red blood cells and platelets.
  • The number and type of white blood cells.
  • The amount of hemoglobin (the protein that carries oxygen) in the red blood cells.
  • The portion of the blood sample made up of red blood cells.

• Sézary blood cell count: A procedure in which a sample of blood is viewed under a microscope to count the number of Sézary cells.
• HIV test: A test to measure the level of HIV antibodies in a sample of blood. Antibodies are made by the body when it is invaded by a foreign substance. A high level of HIV antibodies may mean the body has been infected with HIV.
• Skin biopsy: The removal of cells or tissues so they can be viewed under a microscope to check for signs of cancer. The doctor may remove a growth from the skin, which will be examined by a pathologist. More than one skin biopsy may be needed to diagnose mycosis fungoides. Other tests that may be done on the cells or tissue sample include the following:
  • Immunophenotyping: A laboratory test that uses antibodies to identify cancer cells based on the types of antigens or markers on the surface of the cells. This test is used to help diagnose specific types of lymphoma.
  • Flow cytometry: A laboratory test that measures the number of cells in a sample, the percentage of live cells in a sample, and certain characteristics of the cells, such as size, shape, and the presence of tumor (or other) markers on the cell surface. The cells from a sample of a patient’s blood, bone marrow, or other tissue are stained with a fluorescent dye, placed in a fluid, and then passed one at a time through a beam of light. The test results are based on how the cells that were stained with the fluorescent dye react to the beam of light. This test is used to help diagnose and manage certain types of cancers, such as leukemia and lymphoma.
  • T-cell receptor (TCR) gene rearrangement test: A laboratory test in which cells in a sample of blood or bone marrow are checked to see if there are certain changes in the genes that make receptors on T cells (white blood cells). Testing for these gene changes can tell whether large numbers of T cells with a certain T-cell receptor are being made.

After mycosis fungoides and Sézary syndrome have been diagnosed, tests are done to find out if cancer cells have spread from the skin to other parts of the body.

The process used to find out if cancer has spread from the skin to other partsof the body is called staging. Theinformation gathered from the staging process determines thestage of the disease. It isimportant to know the stage in order to plan treatment.

The followingprocedures may be used in the staging process:

• Chest x-ray: An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body and onto film, making a picture of areas inside the body.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, such as the lymph nodes, chest, abdomen, and pelvis, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• PET scan (positron emission tomography scan): A procedure to find malignant tumor cells in the body. A small amount of radioactive glucose (sugar) is injected into a vein. The PET scanner rotates around the body and makes a picture of where glucose is being used in the body. Malignant tumor cells show up brighter in the picture because they are more active and take up more glucose than normal cells do.
• Lymph node biopsy: The removal of all or part of a lymph node. A pathologist views the lymph node tissue under a microscope to check for cancer cells.
• Bone marrow aspiration and biopsy: The removal of bone marrow and a small piece of bone by inserting a hollow needle into the hipbone or breastbone. A pathologist views the bone marrow and bone under a microscope to look for signs of cancer.

There are three ways that cancer spreads in the body.

Cancer can spread through tissue, the lymph system, and the blood:

• Tissue. The cancer spreads from where it began by growing into nearby areas.
• Lymph system. The cancer spreads from where it began by getting into the lymph system. The cancer travels through the lymph vessels to other parts of the body.
• Blood. The cancer spreads from where it began by getting into the blood. The cancer travels through the blood vessels to other parts of the body.

Cancer may spread from where it began to other parts of the body.

When cancer spreads to another part of the body, it is called metastasis. Cancer cells break away from where they began (the primary tumor) and travel through the lymph system or blood.

• Lymph system. The cancer gets into the lymph system, travels through the lymph vessels, and forms a tumor (metastatic tumor) in another part of the body.
• Blood. The cancer gets into the blood, travels through the blood vessels, and forms a tumor (metastatic tumor) in another part of the body.

The metastatic tumor is the same type of cancer as the primary tumor. For example, if mycosis fungoides spreads to the liver, the cancer cells in the liver are actually mycosis fungoides cells. The disease is metastatic mycosis fungoides, not liver cancer.

The following stages are used for mycosis fungoides and Sézary syndrome:

Stage I Mycosis Fungoides

Stage I is divided into stages IA and IB as follows:

• Stage IA: Patches, papules, and/or plaques cover less than 10% of the skin surface.
• Stage IB: Patches, papules, and/or plaques cover 10% or more of the skin surface.

There may be a low number of Sézary cells in the blood.

Stage II Mycosis Fungoides

Stage II is divided into stages IIA and IIB as follows:

• Stage IIA: Patches, papules, and/or plaques cover any amount of skin surface. Lymph nodes are abnormal, but they are not cancerous.
• Stage IIB: One or more tumors that are 1 centimeter or larger are found on the skin. Lymph nodes may be abnormal, but they are not cancerous.

There may be a low number of Sézary cells in the blood.

Stage III Mycosis Fungoides

In stage III, 80% or more of the skin surface is reddened and may have patches, papules, plaques, or tumors. Lymph nodes may be abnormal, but they are not cancerous.

There may be a low number of Sézary cells in the blood.

Stage IV Mycosis Fungoides/Sézary Syndrome

When there is a high number of Sézary cells in the blood, the disease is called Sézary syndrome.

Stage IV is divided into stages IVA1, IVA2, and IVB as follows:

• Stage IVA1: Patches, papules, plaques, or tumors may cover any amount of the skin surface, and 80% or more of the skin surface may be reddened. The lymph nodes may be abnormal, but they are not cancerous. There is a high number of Sézary cells in the blood.
• Stage IVA2: Patches, papules, plaques, or tumors may cover any amount of the skin surface, and 80% or more of the skin surface may be reddened. The lymph nodes are very abnormal, or cancer has formed in the lymph nodes. There may be a high number of Sézary cells in the blood.
• Stage IVB: Cancer has spread to other organs in the body, such as the spleen or liver. Patches, papules, plaques, or tumors may cover any amount of the skin surface, and 80% or more of the skin surface may be reddened. The lymph nodes may be abnormal or cancerous. There may be a high number of Sézary cells in the blood.

There are different types of treatment for patients with mycosis fungoides and Sézary syndrome cancer.

Different types of treatment are available for patients with mycosis fungoides and Sézary syndrome. Some treatments are standard (the currently used treatment), and some are being tested in clinical trials. A treatment clinical trial is a research study meant to help improve current treatments or obtain information on new treatments for patients with cancer. When clinical trials show that a new treatment is better than the standard treatment, the new treatment may become the standard treatment. Patients may want to think about taking part in a clinical trial. Some clinical trials are open only to patients who have not started treatment.

Seven types of standard treatment are used:

Photodynamic therapy

Photodynamic therapy is a cancer treatment that uses a drug and a certain type of laser light to kill cancer cells. A drug that is not active until it is exposed to light is injected into a vein. The drug collects more in cancer cells than in normal cells. For skin cancer, laser light is shined onto the skin and the drug becomes active and kills the cancer cells. Photodynamic therapy causes little damage to healthy tissue. Patients undergoing photodynamic therapy will need to limit the amount of time spent in sunlight. There are different types of photodynamic therapy:

• In psoralen and ultraviolet A (PUVA) therapy, the patient receives a drug called psoralen and then ultraviolet A radiation is directed to the skin.
• In extracorporeal photopheresis (ECP), the patient is given drugs and then some blood cells are taken from the body, put under a special ultraviolet A light, and put back into the body. ECP may be used alone or combined with total skin electron beam (TSEB) radiation therapy.

Radiation therapy

Radiation therapy is a cancer treatment that uses high-energy x-rays or other types of radiation to kill cancer cells or keep them from growing. External radiation therapy uses a machine outside the body to send radiation toward the area of the body with cancer. Sometimes, total skin electron beam (TSEB) radiation therapy is used to treat mycosis fungoides and Sézary syndrome. This is a type of external radiation treatment in which a radiation therapy machine aims electrons (tiny, invisible particles) at the skin covering the whole body. External radiation therapy may also be used as palliative therapy to relieve symptoms and improve quality of life.

Ultraviolet A (UVA) radiation therapy or ultraviolet B (UVB) radiation therapy may be given using a special lamp or laser that directs radiation at the skin.

Chemotherapy

Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. When chemotherapy is taken by mouth or injected into a vein or muscle, the drugs enter the bloodstream and can reach cancer cells throughout the body (systemic chemotherapy). Sometimes the chemotherapy is topical (put on the skin in a cream, lotion, or ointment).

Other drug therapy

Topical corticosteroids are used to relieve red, swollen, and inflamed skin. They are a type of steroid. Topical corticosteroids may be in a cream, lotion, or ointment.

Retinoids, such as bexarotene, are drugs related to vitamin A that can slow the growth of certain types of cancer cells. The retinoids may be taken by mouth or put on the skin.

Lenalidomide is a drug that helps the immune system kill abnormal blood cells or cancer cells and may prevent the growth of new blood vessels that tumors need to grow.

Vorinostat and romidepsin are two of the histone deacetylase (HDAC) inhibitors used to treat mycosis fungoides and Sézary syndrome. HDAC inhibitors cause a chemical change that stops tumor cells from dividing.

Immunotherapy

Immunotherapy is a treatment that uses the patient's immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body's natural defenses against cancer. This cancer treatment is a type of biologic therapy.

• Interferon: This treatment interferes with the division of mycosis fungoides and Sézary cells and can slow tumor growth.

Targeted therapy

Targeted therapy is a type of treatment that uses drugs or other substances to identify and attack specific cancer cells. Targeted therapies usually cause less harm to normal cells than chemotherapy or radiation therapy do.

• Monoclonal antibodies: Monoclonal antibodies are immune system proteins made in the laboratory to treat many diseases, including cancer. As a cancer treatment, these antibodies can attach to a specific target on cancer cells or other cells that may help cancer cells grow. The antibodies are able to then kill the cancer cells, block their growth, or keep them from spreading. Monoclonal antibodies are given by infusion. They may be used alone or to carry drugs, toxins, or radioactive material directly to cancer cells.

  Types of monoclonal antibodies include:

  • Brentuximab vedotin, which contains a monoclonal antibody that binds to a protein, called CD30, found on some types of lymphoma cells. It also contains an anticancer drug that may help kill cancer cells.
  • Mogamulizumab, which contains a monoclonal antibody that binds to a protein, called CCR4, found on some types of lymphoma cells. It may block this protein and help the immune system kill cancer cells. It is used to treat mycosis fungoides and Sézary syndrome that came back or did not get better after treatment with at least one systemic therapy.

High-dose chemotherapy and radiation therapy with stem cell transplant

High doses of chemotherapy and sometimes radiation therapy are given to kill cancer cells. Healthy cells, including blood-forming cells, are also destroyed by the cancer treatment. Stem cell transplant is a treatment to replace the blood-forming cells. Stem cells (immature blood cells) are removed from the blood or bone marrow of the patient or a donor and are frozen and stored. After the patient completes chemotherapy and radiation therapy, the stored stem cells are thawed and given back to the patient through an infusion. These reinfused stem cells grow into (and restore) the body's blood cells.

Immune checkpoint inhibitor therapy

• Immune checkpoint inhibitor therapy: Immune checkpoint inhibitors block proteins called checkpoints that are made by some types of immune system cells, such as T cells, and some cancer cells. These checkpoints help keep immune responses from being too strong and sometimes can keep T cells from killing cancer cells. When these checkpoints are blocked, T cells can kill cancer cells better.

• PD-1 and PD-L1 inhibitor therapy: PD-1 is a protein on the surface of T cells that helps keep the body’s immune responses in check. PD-L1 is a protein found on some types of cancer cells. When PD-1 attaches to PD-L1, it stops the T cell from killing the cancer cell. PD-1 and PD-L1 inhibitors keep PD-1 and PD-L1 proteins from attaching to each other. This allows the T cells to kill cancer cells. Pembrolizumab is a type of PD-1 inhibitor.

Treatment for mycosis fungoides and Sézary syndrome may cause side effects.

Patients may want to think about taking part in a clinical trial.

For some patients, taking part in a clinical trial may be the best treatment choice. Clinical trials are part of the cancer research process. Clinical trials are done to find out if new cancer treatments are safe and effective or better than the standard treatment.

Many of today's standard treatments for cancer are based on earlier clinical trials. Patients who take part in a clinical trial may receive the standard treatment or be among the first to receive a new treatment.

Patients who take part in clinical trials also help improve the way cancer will be treated in the future. Even when clinical trials do not lead to effective new treatments, they often answer important questions and help move research forward.

Patients can enter clinical trials before, during, or after starting their cancer treatment.

Some clinical trials only include patients who have not yet received treatment. Other trials test treatments for patients whose cancer has not gotten better. There are also clinical trials that test new ways to stop cancer from recurring (coming back) or reduce the side effects of cancer treatment.

Follow-up tests may be needed.

Some of the tests that were done to diagnose the cancer or to find out the stage of the cancer may be repeated. Some tests will be repeated in order to see how well the treatment is working. Decisions about whether to continue, change, or stop treatment may be based on the results of these tests.

Some of the tests will continue to be done from time to time after treatment has ended. The results of these tests can show if your condition has changed or if the cancer has recurred (come back). These tests are sometimes called follow-up tests or check-ups.

Treatment of newly diagnosed stage I and stage II mycosis fungoides may include the following:

• Psoralen and ultraviolet A (PUVA) radiation therapy.
• Ultraviolet B radiation therapy.
• Radiation therapy with total skin electron beam radiation therapy. In some cases, radiation therapy is given to skin lesions, as palliative therapy to reduce tumor size to relieve symptoms and improve quality of life.
• Immunotherapy given alone or combined with therapy directed at the skin.
• Topical chemotherapy.
• Systemic chemotherapy with one or more drugs, which may be combined with therapy directed at the skin.
• Other drug therapy (topical corticosteroids, retinoid therapy, lenalidomide, histone deacetylase inhibitors).
• Targeted therapy (brentuximab vedotin).

Treatment of newly diagnosed stage III and stage IV mycosis fungoides including Sézary syndrome is palliative (to relieve symptoms and improve the quality of life) and may include the following:

• Psoralen and ultraviolet A (PUVA) radiation therapy.
• Ultraviolet B radiation therapy.
• Extracorporeal photochemotherapy given alone or combined with total skin electron beam radiation therapy.
• Radiation therapy with total skin electron beam radiation therapy. In some cases, radiation therapy is given to skin lesions, as palliative therapy to reduce tumor size to relieve symptoms and improve quality of life.
• Immunotherapy given alone or combined with therapy directed at the skin.
• Systemic chemotherapy with one or more drugs, which may be combined with therapy directed at the skin.
• Topical chemotherapy.
• Other drug therapy (topical corticosteroids, lenalidomide, bexarotene, histone deacetylase inhibitors).
• Targeted therapy with brentuximab vedotin.

Recurrent mycosis fungoides and Sézary syndrome have come back in the skin or in other parts of the body after they have been treated.

Treatment of recurrent mycosis fungoides including Sézary syndrome may be within a clinical trial and may include the following:

• Radiation therapy with total skin electron beam radiation therapy. In some cases, radiation therapy is given to skin lesions as palliative therapy to reduce tumor size to relieve symptoms and improve quality of life.
• Psoralen and ultraviolet A (PUVA) radiation therapy, which may be given with immunotherapy.
• Ultraviolet B radiation.
• Extracorporeal photochemotherapy.
• Systemic chemotherapy with one or more drugs.
• Other drug therapy (topical corticosteroids, retinoid therapy, lenalidomide, histone deacetylase inhibitors).
• Immunotherapy given alone or combined with therapy directed at the skin.
• High-dose chemotherapy, and sometimes radiation therapy, with stem cell transplant.
• Targeted therapy (brentuximab vedotin or mogamulizumab).

Certain factors affect prognosis (chance of recovery) and treatment options.

The prognosis and treatment options depend on the following:

• The stage of the cancer.
• The type of lesion (patches, plaques, or tumors).
• The patient's age and gender.

Mycosis fungoides and Sézary syndrome are hard to cure. Treatment is usually palliative, to relieve symptoms and improve the quality of life. Patients with early stage disease may live many years.