Health information to help you understand symptoms. It isn't a diagnosis.
Check symptoms

Mycosis fungoides and Sézary syndrome (skin T-cell lymphoma)

Also called: Sezary syndrome, Cutaneous t-cell lymphoma, CTCL

A slow-growing lymphoma that shows up in the skin, often mistaken for eczema for years.

Typical age50 to 60
More common inMen and Black adults

Overview

Mycosis fungoides begins as flat patches, may become thicker plaques, and rarely forms tumors. Many people stay in the early patch stage for life.

A skin biopsy, sometimes more than one, is needed to diagnose it. Early disease is treated with creams and light therapy; advanced disease uses medicines taken by mouth or into a vein.

Symptoms

Common signs:

  • Red, scaly, itchy patches, often on skin covered by clothes
  • Patches that don't go away with eczema creams

Less common

  • Thicker raised plaques or skin lumps
  • Red skin over most of the body with severe itching (Sézary syndrome)
  • Swollen glands

Look up a symptom: Dry or scaly skin · Itching · Red spot, bump, or patch on the skin · Swollen glands · Thick, scaly, silvery patches

When to get medical care

Call 911Trouble breathing, heavy bleeding, a seizure, sudden confusion, or fainting: call 911.
Get care todayFever during cancer treatment, or new or quickly worsening symptoms.
See a doctor soonSymptoms lasting more than 2 to 3 weeks.

Causes

Changes in a cell's genes that make it grow out of control. Most happen by chance; some are linked to the risk factors below or to inherited genes.

Does it spread or run in families?

  • Cancer isn't contagious. You can't catch it from someone.

Who is more likely to get it

  • Older age
  • Male sex

Diagnosis

Tests look for the cause. Many people checked for these symptoms turn out not to have cancer.

Questions you may be asked

  • When symptoms started and whether they're getting worse
  • Family history of cancer
  • Past illnesses, treatments, and exposures

The exam

A physical exam, focused on where the symptoms are.

Tests

Tests, if needed:

  • Skin biopsy: Sometimes repeated before it's clear.
  • Blood test for Sézary cells:

Treatment

Treatment depends on the type, stage, and your overall health. A cancer care team makes a plan with you.

Self-care

  • Write down symptoms and when they started
  • Bring someone with you to appointments
  • Ask for copies of test results
  • Ask about clinical trials: they can offer new treatments
  • Quit smoking: it helps at every stage

Steroid creams, light therapy (phototherapy), skin-directed chemotherapy gels, radiation, or medicines by mouth or IV.

Prevention

To lower risk or find it early:

  • No proven way to prevent it

Which doctor treats this

  • Start with your primary care provider (family doctor or internist).
  • They may send you to an oncologist (cancer doctor), often working with surgeons and radiation doctors.

Living with it

  • Keep a simple notebook of symptoms, medicines, and questions for visits.
  • Ask for a survivorship care plan when treatment ends.
  • Gentle activity, like walking, can ease tiredness.
  • A cancer diagnosis can affect mood. Tell the care team if you or your family feel down or anxious.

Support groups and helplines

Back to school, work, or sports

  • Many people keep working during or after treatment.
  • Ask about changes that help, like flexible hours. Workers may be covered by the ADA.

Pregnancy and breastfeeding

  • If you're pregnant or planning to be, tell your cancer team. Some treatments can harm a baby.
  • Ask about saving eggs or sperm before treatment if you may want children later.

For caregivers

  • Go to visits when you can and take notes.
  • Keep a list of medicines, allergies, and doctors in one place.
  • Learn the warning signs that need fast care, like fever during treatment.
  • Take breaks and ask for help. Caregivers need care too.

Outlook

Outlook depends on the type and stage. Cancers found early are usually easier to treat, and treatments keep improving.

Support is available: ask about social workers, nutrition help, and support groups.

Getting ready for your visit

Bring a list of symptoms and medicines.

What to bring

  • A list of medicines and supplements
  • Notes on when symptoms started
  • Past test results and scans

Questions to ask

  • Do I need another skin biopsy?
  • Which skin treatments should I try first?
  • What stage is it, and what are the treatment options?
  • Are there clinical trials for me?

Research studies

Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.

Search ClinicalTrials.gov for studies on Mycosis fungoides and Sézary syndrome (skin T-cell lymphoma)

Sources

Last updated 2026-11-13.