Key takeaways
- Mycosis fungoides is a rare type of cutaneous T-cell lymphoma. It develops when T cells mutate into cancer cells. The exact trigger for these mutations remains unclear, but it may involve bacterial overgrowth, viruses, or environmental chemicals.
- This skin cancer progresses slowly through distinct stages, beginning with rash-like patches that can be mistaken for eczema or psoriasis. After years or decades, the patches may thicken into plaques and potentially spread to internal organs in advanced stages.
- While there is no cure, approximately 70% of cases are in early stages at the time of diagnosis, and this is when treatment is most effective. Treatment can include topical corticosteroids and light therapy in the early stages, and systemic chemotherapy and targeted medications for advanced stages.
Mycosis fungoides is a rare kind of skin cancer called cutaneous T-cell lymphoma. It is also called granuloma fungoides. It may look like a fungal rash, but it is not caused by a fungus.
Mycosis fungoides is a chronic condition that can slowly worsen over time. Like other cancers, it can spread to other parts of the body in later stages, like the digestive system, liver, or brain.
Early diagnosis and treatment are important for the best health outcomes.
Read on to learn more about mycosis fungoides and what to do if you think you have symptoms of the condition.
Doctors are not sure of the exact causes of mycosis fungoides and other T-cell lymphomas.
Mycosis fungoides may begin when T cells change or mutate and turn into cancer cells. T cells or T lymphocytes are white blood cells that usually help the immune system protect the body.
It’s not clear what causes T-cells to change. Some studies found that certain bacteria, viruses, or chemicals from the environment may play a role in causing mycosis fungoides.
For example, in a
People in this study showed improvement in symptoms when they took antibiotic medication that reduced this bacteria type.
Genetics and other factors may also increase the risk of getting mycosis fungoides. Some types of genetic or chromosomal mutations may increase the risk. A 2015 clinical study found that 18% of people with mycosis fungoides or Sezary syndrome had the same genetic mutations.
What is Sézary syndrome?
Sézary syndrome is a related condition where irregular T cells from the skin make their way into the blood, according to
Sézary syndrome is a more aggressive form of T-cell lymphoma. Its main feature is erythroderma, which is skin redness or discoloration that covers the whole body. In its early stages, it can look like eczema.
In addition to erythroderma, people with Sézary syndrome may have:
- soreness
- swelling over much of their body
- severe itching
Mycosis fungoides is also more likely to happen in people between the ages of 40 and 60 years, though it may develop at any time.
While most people with mycosis fungoides are white, the incidence rate is higher among Black people. According to a
Symptoms of mycosis fungoides can look like symptoms of some common and less serious skin conditions, such as eczema or psoriasis.
Since mycosis fungoides usually develops very slowly, it may look like a skin rash or scaly patch of skin for years or decades. Because of this, people with this skin cancer may at first receive a misdiagnosis.
Mycosis fungoides symptoms vary depending on the stage. At the start, mycosis fungoides may look like a sunburn or rash. It typically begins on any area of the skin that does not get much sun.
The color of skin lesions may also vary in color, and may appear purple, gray, or brown. It can also cause:
- skin redness or irritation
- scaly or shiny patches
- flat skin lesions
- thicker or raised plaques
- large skin nodules
The rash will eventually turn into flat, scaly patches that may look like common skin conditions such as eczema or psoriasis. In some people, this stage may look like light spots. This is more common in children, teenagers, and people with darker skin tones.
Patches eventually thicken and raise, forming plaques that may look like thicker skin or welts. These plaques may also be itchy and resemble other common and less-serious skin conditions.
Individuals with late stage mycosis fungoides may have worse overall symptoms and quality of life than people with the condition in an earlier stage.
Doctors break mycosis fungoides into
- Stage 1: The skin has patches or plaques, but nothing has spread to the blood, lymph nodes, or other organs.
- 1A: Patches or plaques cover less than 10% of the body.
- 1B: Patches or plaques cover 10% or more of the body.
- Stage II: In addition to patches or plaques on the skin, the lymph nodes are enlarged but not cancerous.
- 2A: There are no tumors on the skin.
- 2B: There is at least one tumor on the skin.
- Stage III: More than 80% of the skin is affected by patches, plaques, or tumors. The lymph nodes may be enlarged, but they’re not cancerous.
- Stage IV: In addition to most of the skin being affected, there is a high number of Sézary cells or the cancer has begun to spread.
- IVA1. The lymph nodes are enlarged but not cancerous. There is also a high number of Sézary cells in the blood.
- IVA2: There may be cancer in the lymph nodes, but it has not spread to other parts of the body.
- IVB: Cancer has spread to other organs, such as the liver or spleen.
You may need several tests before a doctor can diagnose mycosis fungoides. These
- physical exams
- skin biopsies, where doctors examine a small sample of your skin
- lymph or tissue biopsies
- blood tests
In some cases, this skin condition will not show up in a skin biopsy or blood test. A doctor will need to perform more tests.
Specialized tests may look at T cells in the blood, and CT scans and PET scans can look at the organs. A doctor may also recommend a genetic test.
Similar tests can also help a doctor understand what stage of mycosis fungoides you may have.
Treatment for mycosis fungoides depends on the stage of this condition.
Some treatments help control symptoms like skin soreness, swelling, and itching.
Standard therapies and management for earlier stages of this skin condition mainly involve topical (skin) therapies
- photochemotherapy
- ultraviolet light therapy
- topical steroid cream
- oral retinoid therapy
- photopheresis
- imiquimod
The goals of later-stage treatments for mycosis fungoides are to shrink tumors and slow the spread of cancer cells. Treatment may involve both internal and external treatment, including:
- interferon injections
- radiation therapy
- mechlorethamine topical gel
- mogamulizumab-kpkc injection (Poteligeo)
- stem cell transplant
- brentuximab-vedotin (Adcetris)
- chemotherapy
Some therapies and medications for mycosis fungoides and other types of cancers can cause serious side effects that may limit how much treatment you receive.
There is currently no cure for mycosis fungoides. However, this skin condition is slow-growing, and your outlook depends on the stage and treatment.
Around 70% of people with mycosis fungoides are at the early stage when a doctor diagnoses them. This means there’s a higher chance that treatment will be effective with positive health outcomes.
Survival rates for people with mycosis fungoides vary and depend on the stage at diagnosis and treatment. According to a 2020 review of studies, the 5-year survival rates for people with mycosis fungoides by stage were:
- Stage 1B: 85.8%
- Stage 2B: 62.2%
- Stage 3A: 59.7%
- Stage 3B: 54.0%
- Stage 4A1: 52.5%
- Stage 4A2: 34.0%
- Stage 4B: 23.3%
Your doctor can provide more information on your outlook based on individual circumstances.
Mycosis fungoides is not contagious and cannot spread from person to person.
Mycosis fungoides is not known to be hereditary. There is a common gene mutation found in some people with mycosis fungoides, but it is not likely to be inherited or passed down in families.
This type of cutaneous lymphoma is very slow-growing. In some cases, it can take some time to make an accurate diagnosis.
Mycosis fungoides is a rare type of cutaneous T-cell lymphoma. It begins on the skin and can spread to the body through the lymph nodes. It can cause symptoms such as a rash, scaly skin, and shiny patches.
Mycosis fungoides is slow growing, especially in the early stages. Various types of treatments can help alleviate symptoms.
Diagnosis can be difficult because mycosis fungoides often looks like other common skin conditions, such as eczema and psoriasis. Contact a doctor right away if you notice any rashes on your skin or think you may have this skin condition. They can confirm the diagnosis and advise on suitable treatments.