Key Points for This Section

Mycosis fungoides and the Sézary syndrome are diseases in which lymphocytes (a type of white blood cell) become malignant (cancerous) and affect the skin. Mycosis fungoides and the Sézary syndrome are types of cutaneous T-cell lymphoma. A possible sign of mycosis fungoides and the Sézary syndrome is a red rash on the skin. Sézary syndrome is an advanced form of mycosis fungoides. Tests that examine the skin and blood are used to detect (find) and diagnose mycosis fungoides and the Sézary syndrome. Certain factors affect prognosis (chance of recovery) and treatment options.

Mycosis fungoides and the 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 develop into mature blood stem cells over time. A blood stem cell may become a myeloid stem cell or a lymphoid stem cell. The myeloid stem cell develops into a red blood cell, white blood cell, or platelet. The lymphoid stem cell develops into a lymphoblast and then into 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.

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Blood cell development. A blood stem cell goes through several steps to become a red blood cell, platelet, or white blood cell.

In mycosis fungoides, T-cell lymphocytes become cancerous and affect the skin. In the Sézary syndrome, cancerous T-cell lymphocytes affect the skin and the peripheral blood.

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

This summary describes the two most common types of cutaneous T-cell lymphomas: mycosis fungoides and the Sézary syndrome. For information about other types of skin cancer or non-Hodgkin lymphoma, see the following PDQ summaries:

• Adult Non-Hodgkin Lymphoma Treatment ¹
• Skin Cancer Treatment ²
• Melanoma Treatment ³
• Kaposi Sarcoma Treatment ⁴

A possible sign of mycosis fungoides and the Sézary syndrome is a red rash on the skin.

Mycosis fungoides and the Sézary syndrome may move 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: Thickened, red patches or reddened skin.
• Tumor phase: Tumors form on the skin. These tumors may develop ulcers and the skin may get infected.

Sézary syndrome is an advanced form of mycosis fungoides.

In the Sézary syndrome, skin all over the body is reddened, itchy, peeling, and painful. There may also be patches, plaques, or tumors on the skin. Cancerous T-cells are found in the blood. Mycosis fungoides does not always progress to the Sézary syndrome.

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

The following tests and procedures may be used:

• Physical exam and 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.

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  Complete blood count (CBC). Blood is collected by inserting a needle into a vein and allowing the blood to flow into a tube. The blood sample is sent to the laboratory and the red blood cells, white blood cells, and platelets are counted. The CBC is used to test for, diagnose, and monitor many different conditions.

• Peripheral blood smear: A procedure in which a sample of blood is viewed under a microscope to count different circulating blood cells (red blood cells, white blood cells, platelets, etc.) and see whether the cells look normal.
• 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.
• Immunophenotyping: A process used to identify cells, based on the types of antigens or markers on the surface of the cell. This process may include special staining of the blood cells. It is used to diagnose specific types of leukemia and lymphoma by comparing the cancer cells to normal cells of the immune system.
• Immunogenotyping: A procedure in which a sample of DNA from a skin biopsy is studied to see if the genes for certain kinds of immune system proteins, such as the T-cell receptor or antibody proteins, are arranged in one pattern. Normally T-cell receptor genes and antibody genes are arranged in many different patterns. In mycosis fungoides and the Sézary syndrome, the genes are arranged in a single pattern.

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

The prognosis (chance of recovery) and treatment options depend on the following:

• The stage of the cancer (the amount of skin affected and whether cancer has spread to the lymph nodes, the blood, or other places in the body).
• The type of lesion (patches, plaques, or tumors).
• The number of cutaneous T-cell lymphocytes in the blood.

Mycosis fungoides and the Sézary syndrome are difficult to cure. Treatment is usually palliative, to relieve symptoms and improve the quality of life. Patients can live many years with this disease.

Glossary Terms

A type of protein made by plasma cells (a type of white blood cell) in response to an antigen (foreign substance). Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen. Antibodies can work in several ways, depending on the nature of the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen.

A substance that causes the immune system to make a specific immune response.

A type of immune cell that makes proteins called antibodies, which bind to microorganisms and other foreign substances, and help fight infections. A B cell is a type of white blood cell. Also called B lymphocyte.

A type of immune cell that makes proteins called antibodies, which bind to microorganisms and other foreign substances, and help fight infections. A B lymphocyte is a type of white blood cell. Also called B cell.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

The soft, sponge-like tissue in the center of most bones. It produces white blood cells, red blood cells, and platelets.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A test to check the number of red blood cells, white blood cells, and platelets in a sample of blood. Also called blood cell count and CBC.

To heal or restore health; a treatment to restore health.

Having to do with the skin.

The process of identifying a disease, such as cancer, from its signs and symptoms.

The molecules inside cells that carry genetic information and pass it from one generation to the next. Also called deoxyribonucleic acid.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

The substance inside red blood cells that binds to oxygen in the lungs and carries it to the tissues.

The complex group of organs and cells that defends the body against infections and other diseases.

A process used to identify cells, based on the types of antigens or markers on the surface of the cell. This process is used to diagnose specific types of leukemia and lymphoma by comparing the cancer cells to normal cells of the immune system.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

An area of abnormal tissue. A lesion may be benign (not cancer) or malignant (cancer).

Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of blood cells to be produced and enter the bloodstream.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

A lymphocyte that has gotten larger after being stimulated by an antigen. Lymphoblast also refers to an immature cell that can develop into a mature lymphocyte.

A type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue. The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses. A lymphocyte is a type of white blood cell.

Referring to lymphocytes, a type of white blood cell. Also refers to tissue in which lymphocytes develop.

Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

A diagnostic indication that disease may develop.

A type of non-Hodgkin lymphoma that first appears on the skin and can spread to the lymph nodes or other organs such as the spleen, liver, or lungs.

In mycosis fungoides, an area of skin that is thickened, raised, red, scaly, and itchy.

Having to do with or resembling the bone marrow. May also refer to certain types of hematopoietic (blood-forming) cells found in the bone marrow. Sometimes used as a synonym for myelogenous; for example, acute myeloid leukemia and acute myelogenous leukemia are the same disease.

A type of immune cell that has granules (small particles) with enzymes that can kill tumor cells or cells infected with a virus. A natural killer cell is a type of white blood cell. Also called NK cell and NK-LGL.

Any of a large group of cancers of lymphocytes (white blood cells). Non-Hodgkin lymphomas can occur at any age and are often marked by lymph nodes that are larger than normal, fever, and weight loss. There are many different types of non-Hodgkin lymphoma. These types can be divided into aggressive (fast-growing) and indolent (slow-growing) types, and they can be formed from either B-cells or T-cells. B-cell non-Hodgkin lymphomas include Burkitt lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), diffuse large B-cell lymphoma, follicular lymphoma, immunoblastic large cell lymphoma, precursor B-lymphoblastic lymphoma, and mantle cell lymphoma. T-cell non-Hodgkin lymphomas include mycosis fungoides, anaplastic large cell lymphoma, and precursor T-lymphoblastic lymphoma. Lymphomas that occur after bone marrow or stem cell transplantation are usually B-cell non-Hodgkin lymphomas. Prognosis and treatment depend on the stage and type of disease. Also called NHL.

Treatment given to relieve the symptoms and reduce the suffering caused by cancer and other life-threatening diseases. Palliative cancer therapies are given together with other cancer treatments, from the time of diagnosis, through treatment, survivorship, recurrent or advanced disease, and at the end of life.

A doctor who identifies diseases by studying cells and tissues under a microscope.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

Blood circulating throughout the body.

A procedure in which a sample of blood is viewed under a microscope to count different circulating blood cells (red blood cells, white blood cells, platelets, etc.) and see whether the cells look normal.

An exam of the body to check for general signs of disease.

A tiny piece of a cell found in the blood that breaks off from a large cell found in the bone marrow. Platelets help wounds heal and prevent bleeding by forming blood clots. Also called thrombocyte.

A phase of mycosis fungoides in which a patient has areas of red, scaly, itchy skin on areas of the body that are usually not exposed to sun. This is early-phase mycosis fungoides, but it is hard to diagnose the rash as mycosis fungoides during this phase. The premycotic phase may last from months to decades.

The likely outcome or course of a disease; the chance of recovery or recurrence.

Cancer that is growing, spreading, or getting worse.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life. These studies measure aspects of an individual’s sense of well-being and ability to carry out various activities.

A molecule inside or on the surface of a cell that binds to a specific substance and causes a specific physiologic effect in the cell.

A cell that carries oxygen to all parts of the body. Also called erythrocyte and RBC.

A form of cutaneous T-cell lymphoma, a cancerous disease that affects the skin.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

A cell from which other types of cells develop. For example, blood cells develop from blood-forming stem cells.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

A set of symptoms or conditions that occur together and suggest the presence of a certain disease or an increased chance of developing the disease.

A type of immune cell that can attack foreign cells, cancer cells, and cells infected with a virus. T cells can also help control immune responses. A T cell is a type of white blood cell. Also called T lymphocyte and thymocyte.

A group or layer of cells that work together to perform a specific function.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

The formation of a break on the skin or on the surface of an organ. An ulcer forms when the surface cells die and are cast off. Ulcers may be associated with cancer and other diseases.

In medicine, a very simple microorganism that infects cells and may cause disease. Because viruses can multiply only inside infected cells, they are not considered to be alive.

A type of immune cell. Most white blood cells are made in the bone marrow and are found in the blood and lymph tissue. White blood cells help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are white blood cells. Also called leukocyte and WBC.