Sezary syndrome

Find out more about the symptoms, diagnosis and treatment of this rare type of cancer.

Update Date: 03.02.2026

Overview
Symptoms
Causes
Risk factors
Complications
Diagnosis
Treatment
Coping and support
Preparing for an appointment
Stages

Overview

Sezary syndrome is a type of lymphoma that affects the skin and other parts of the body. Lymphoma is cancer that happens in the lymphatic system, which is part of the body's germ-fighting immune system.

Sezary syndrome mostly affects the skin, which is why this cancer is considered a type of cutaneous T-cell lymphoma. But Sezary syndrome also affects the blood, which makes it different from other types of lymphoma. Healthcare professionals sometimes say it is a leukemic variant of cutaneous T-cell lymphoma because Sezary syndrome has some features of both lymphoma and leukemia, which is a cancer of the blood and bone marrow.

Some people wonder how Sezary syndrome relates to another condition called mycosis fungoides. Mycosis fungoides happens mostly in the skin, while Sezary syndrome affects the skin, blood and lymph nodes. This suggests that Sezary syndrome and mycosis fungoides are related but distinct conditions. Some people may show features of both conditions at the same time. In some people, mycosis fungoides can progress into Sezary syndrome.

Sezary syndrome can't be cured, but many treatments can help reduce symptoms, improve the skin and slow the growth of the cancer. Treatment often involves skin-directed therapies and systemic treatments that work throughout the whole body. These treatments help manage the disease and improve quality of life.

Sezary syndrome and other T-cell lymphomas are types of non-Hodgkin lymphoma.

Symptoms

Symptoms of Sezary syndrome typically happen fast and affect the whole body. Signs and symptoms may include:

  • Severe skin itching, burning or discomfort.
  • A scaly rash that causes the skin to look red, purple or gray depending on skin color, a condition known as erythroderma.
  • Swollen lymph nodes, which may feel like lumps under the skin. They happen most often in the neck, armpit and groin.
  • Thickened skin on the hands and feet.
  • Tight or thickened skin around the eyes that causes the eyelid to turn outward. This is known as ectropion.
  • Hair loss, including loss of eyebrows or body hair.
  • Nail changes, such as thick or brittle nails.

When to see a doctor

Make an appointment with a healthcare professional if you have any symptoms that worry you.

Causes

It's not clear what causes Sezary syndrome. Cancer happens when cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time. In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to make many more cells quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells. In Sezary syndrome, the cancer cells can build up in the skin, blood and lymph nodes.

Sezary syndrome gets its name from the type of cells involved. In this cancer, a type of white blood cell called a T lymphocyte transforms into a cell called a Sezary cell. These cells circulate in the blood and build up in the skin.

Risk factors

Factors that may increase the risk of Sezary syndrome include:

  • Older age. Sezary syndrome happens most often in older adults
  • Mycosis fungoides. In some people, mycosis fungoides can progress into Sezary syndrome.

There are no known ways to prevent Sezary syndrome.

Complications

Sezary syndrome may cause complications such as:

  • Frequent infections. People with Sezary syndrome are more likely to get infections because the skin barrier is damaged and the immune system is weakened. These infections can be serious and may include bacterial, viral or fungal infections.
  • A switch to a more aggressive form of cancer. In some people, the cancer cells can change into larger and more aggressive cells that grow more quickly and make treatment more difficult. Healthcare professionals sometimes refer to this as a large cell transformation.
  • Increased risk of other cancers. People with Sezary syndrome have a higher risk of developing other cancers, including skin cancers and lymphomas.

Diagnosis

Diagnosis and tests

Diagnosis of Sezary syndrome often begins with a physical exam. The exam checks the skin for changes and checks for swollen lymph nodes in the neck, underarms and groin. Other tests and procedures include blood tests, imaging tests and taking a sample of tissue for lab testing.

Skin exam

A healthcare professional examines the skin for changes. Sezary syndrome often causes a rash and skin changes that develop quickly and cover most of the body.

Biopsy

A biopsy is a procedure to remove a sample of tissue for testing in a lab. Your healthcare professional may remove a small sample or multiple samples of the affected skin. The sample is tested in a lab to look for cancer cells.

Your healthcare professional also may suggest a lymph node biopsy to look for cancer cells. A lymph node biopsy involves removing all or part of a lymph node.

Blood tests

Tests and procedures used to diagnose Sezary syndrome include blood tests that:

  • Measure the number of lymphocytes in the blood. A complete blood count (CBC) can show if lymphocyte levels are higher than expected. Although this does not diagnose Sezary syndrome on its own, a high lymphocyte count can be a sign that further testing is needed.
  • Look for Sezary cells. A peripheral blood smear may be used to count the number of Sezary cells in a blood sample. Sezary cells are the cancerous T lymphocytes that happen in people with Sezary syndrome. When looked at under a microscope, Sezary cells are larger than healthy lymphocytes. Their centers, called nuclei, look folded with deep grooves, giving them a brainlike appearance. A high number of Sezary cells present in the blood could mean Sezary syndrome.
  • Identify proteins on the surface of the cancer cells. Sezary cells have certain proteins on their surfaces that help identify them. These proteins are known as markers.
  • Look for changes in the cancer cell DNA. Cancer happens when cells get changes in their DNA. Lab tests can show which DNA changes are present in the cancer cells.
  • Measure levels of lactate dehydrogenase. Lactate dehydrogenase (LDH) levels in the blood are often higher in people with lymphoma.
  • Check for viruses. Blood tests can check for viruses, including human immunodeficiency virus (HIV), hepatitis B and hepatitis C. The presence of a virus may affect treatment options.

Imaging tests

Imaging tests make pictures of the body. A healthcare professional may recommend imaging tests for Sezary syndrome to check the lymph nodes or see if the cancer has spread to the organs. Imaging tests may be done on the neck, chest, belly and pelvis. Tests might include CT and positron emission tomography (PET) scans.

Treatment

Treatments for Sezary syndrome include skin-directed therapies and systemic treatments that work throughout the whole body. These treatments help manage the disease and improve quality of life. Which treatment is right for you depends on your symptoms, how quickly the cancer is growing, your overall health and what you prefer.

Skin-directed therapies

Skin-directed therapies are treatments that are used on the skin. These treatments can ease symptoms such as color changes in the skin and itching. You may get a combination of skin-directed therapies. Skin-directed therapies also may be combined with systemic treatments. For Sezary syndrome, skin-directed therapies include:

  • Topical medicines. These are medicines that are applied directly to the skin to help reduce color changes and itching. Options may include topical corticosteroids, chemotherapy and retinoids.
  • Phototherapy. Phototherapy treats skin symptoms with ultraviolet light. In Sezary syndrome, it may help with color changes, scaling, itching and the discomfort caused by the widespread skin changes.
  • Total skin electron beam therapy (TSEBT). This treatment is a type of radiation therapy that uses electrons instead of X-rays. The electron beams don't penetrate as deeply as X-rays, so they are ideal for treating cancers that are limited to the skin. TSEBT may help with skin symptoms.

Systemic treatments

These treatments help treat cancer throughout the body, including the skin, blood, lymph nodes and internal organs. Systemic treatments may be combined with skin-directed therapies. You also may receive a combination of systemic treatments. For Sezary syndrome, systemic treatments include:

  • Extracorporeal photopheresis (ECP). In ECP, a machine draws blood from the body and treats it with a light-activated medicine. The medicine damages cancer cells. Then the machine returns the treated blood to the body. This process helps your immune system recognize and attack Sezary cells. ECP can improve both skin and blood symptoms.

  • Targeted therapy. Targeted therapy for cancer is a treatment that uses medicines that attack specific proteins in cancer cells. By blocking these proteins, targeted treatments can cause cancer cells to die.

    For Sezary syndrome, this treatment attacks the Sezary cells. You may take a combination of targeted therapy medicines. Targeted therapy also may be used when other treatments haven't worked, known as refractory Sezary syndrome. Or it may be used for cancer that comes back after treatment, called relapsed Sezary syndrome.

  • Immunotherapy. Immunotherapy for cancer is a treatment with medicine that helps the body's immune system kill cancer cells. The immune system fights off diseases by attacking germs and other cells that shouldn't be in the body. Cancer cells survive by hiding from the immune system. Immunotherapy helps the immune system cells find and kill the cancer cells.

    For Sezary syndrome, immunotherapy is often a first line treatment because it can help treat the skin and the blood. Immunotherapy also may be used for refractory Sezary syndrome.

  • Histone deacetylase (HDAC) inhibitors. HDAC inhibitors are medicines that help stop cancer cells from growing. They are often used to treat advanced Sezary syndrome or refractory Sezary syndrome. These medicines can help control symptoms and reduce itching.

  • Chemotherapy. Chemotherapy treats cancer with strong medicines. There are many chemotherapy medicines. Most chemotherapy medicines are given through a vein. Some come in pill form.

    Chemotherapy may be a treatment for Sezary syndrome that is quickly getting worse. It may be an option when other treatments haven't worked or the cancer spreads to the internal organs. Chemotherapy also may be used for Sezary syndrome that has undergone a large cell transformation and become more aggressive.

  • Bone marrow transplant. A bone marrow transplant, also called a bone marrow stem cell transplant, involves putting healthy bone marrow stem cells into the body. These cells replace cells hurt by chemotherapy and other treatments. For Sezary syndrome, the stem cells come from a donor, called an allogeneic transplant.

    Because a bone marrow transplant has high risks, it may be considered only for certain people. A healthcare professional may recommend a bone marrow transplant for someone with advanced Sezary syndrome or when multiple prior treatments haven't worked. Chemotherapy is typically done before the transplant to suppress the immune system and bone marrow.

Coping and support

With time, you'll likely find what helps you cope with the uncertainty and worry of a cancer diagnosis. Until then, you may find that it helps to:

Learn enough about Sezary syndrome to make decisions about your care

Ask your healthcare team about your cancer, including your test results, treatment options and, if you want, your prognosis. As you learn more about Sezary syndrome, you may become more confident in making treatment decisions.

Keep friends and family close

Keeping your close relationships strong can help you deal with your Sezary syndrome. Friends and family can provide the practical support you may need, such as helping take care of your home if you're in the hospital. And they can serve as emotional support when you feel overwhelmed by having cancer.

Find someone to talk with

Find someone who is willing to listen to you talk about your hopes and worries. This person may be a friend or family member. The concern and understanding of a counselor, medical social worker, clergy member or cancer support group also may be helpful.

Ask your healthcare team about support groups in your area. Other sources of information include the National Cancer Institute, the American Cancer Society, Blood Cancer United and the Lymphoma Research Foundation. Find support online through Mayo Clinic Connect, which is a community where you can connect with others for support, practical information and answers to everyday questions.

Preparing for an appointment

Make an appointment with a healthcare professional if you have any symptoms that worry you.

If your healthcare professional thinks you might have Sezary syndrome, you may be referred to a doctor who specializes in diseases that affect blood cells, called a hematologist. If a cancer diagnosis is made, you also may be referred to a doctor who specializes in treating cancer, called an oncologist.

Because appointments can be brief, it's a good idea to be prepared. Here's some information to help you get ready.

What you can do

  • Be aware of anything you need to do ahead of time. At the time you make the appointment, ask if there's anything you need to do in advance, such as restrict your diet.
  • Write down symptoms you have, including any that may not seem related to the reason for which you scheduled the appointment.
  • Write down important personal information, including major stresses or recent life changes.
  • Make a list of all medicines, vitamins and supplements you're taking and the doses.
  • Take a family member or friend along. It can be hard to remember all the information you get during an appointment. Someone who goes with you may remember something that you missed or forgot.
  • Write down questions to ask your healthcare team.

For Sezary syndrome, some basic questions include:

  • Do I have Sezary syndrome?
  • What is the stage of my Sezary syndrome?
  • Will I need more tests?
  • What are the treatment options?
  • How much does each treatment prolong my life?
  • What are the potential side effects of each treatment?
  • How will each treatment affect my daily life?
  • What treatment options have shown the best results?
  • What would you recommend to a friend or family member in my situation?
  • Should I see a specialist?
  • Are there any brochures or other printed material that I can take with me? What websites do you recommend?
  • What will determine whether I should plan for a follow-up visit?

Don't hesitate to ask other questions.

What to expect from your doctor

Be prepared to answer questions, such as:

  • When did your symptoms begin?
  • Do your symptoms happen all the time or do they come and go?
  • How bad are your symptoms?
  • What, if anything, seems to make symptoms better?
  • What, if anything, seems to make symptoms worse?
  • Have you noticed any skin color changes or any itching or discomfort anywhere on your body?
  • What are your biggest worries about your diagnosis or treatment?

Stages

If you're diagnosed with Sezary syndrome, the next step is to determine the cancer's extent, called the stage. Biopsies, imaging tests and blood tests may be used to determine the stage of your Sezary syndrome. Your healthcare team uses the cancer stage to help create your treatment plan.

Sezary syndrome is unique because it almost always is a stage 4. This is because of the widespread skin involvement and the high number of Sezary cells in the blood. There are different types of stage 4 depending on whether the lymph nodes are involved and if the cancer has spread to the internal organs. The stages are:

  • Stage 4A1. At this stage, there is some lymph node involvement.
  • Stage 4A2. At this stage, the lymph node involvement is more significant.
  • Stage 4B. At this stage, the cancer has spread to the internal organs.

Because Sezary syndrome is almost always a stage 4, it is considered an advanced cancer.

Sezary syndrome prognosis

The cancer prognosis tells you how likely it is that the cancer can be treated successfully. Sezary syndrome has a more serious outlook than other types of lymphomas that affect the skin. Many studies report average survival of 2 to 5 years. Your personal prognosis may be different and can depend on factors, including:

  • Your age.
  • Your overall health.
  • The stage of your cancer.
  • If your cancer has spread beyond the skin and blood.
  • Your blood test results.

Talk with your healthcare team about your prognosis if you want to know what to expect. Members of your healthcare team can explain what they consider when thinking about your prognosis.

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