What Is Mycosis Fungoides?


Mycosis fungoides (MF) is a type of skin cancer caused by abnormal white blood cells collecting in the skin.Cancers arising from white blood cells or lymphocytes are broadly called lymphomas, and those occurring in the skin are known as cutaneous lymphomas.1, 6 MF starts as a skin rash and generally follows a slow progression. Treatment is aimed at controlling the symptoms.

What is mycosis fungoides?

Mycosis fungoidesis (MF) is one of the most common cutaneous lymphomas, which occurs when T lymphocytes, a type of lymphocyte, become cancerous.7 The condition occurs as a rash on your skin that doesn't seem to go away. The rash usually occurs in body parts that are not exposed to the sun. This is sometimes called the ‘bathing suit ‘distribution.The rash goes through different phases, changing its appearance. Mycosis fungoides occurs more commonly in adults, although it can rarely occur in children, with a slightly different rash on the skin.9

The best way to diagnose this is through a biopsy, skin sampling, and testing it under a microscope. Sometimes, additional lab tests called immunohistochemistry are used on the biopsies for confirmation. 

The connection of mycosis fungoides with other diseases

It is closely related to Sézary syndrome. In this condition, the abnormal lymphocytes affect the skin, and on investigation, circulating sezary cells are found in the blood.1

MF can sometimes be confused with conditions that cause the collection of white blood cells in the skin, such as infection and lichenoid conditions. It is also necessary to exclude other aggressive skin cancers before confirming mycosis fungoides.5,7

The treatment of mycosis fungoides varies depending on the clinical stage and is aimed at controlling the disease progression and symptoms.6

What causes mycosis fungoides?

The exact cause of MF is unknown. The factors that can increase the risk or cause MF include:

  • Genetic mutation- Alteration in genetic material can lead to the multiplication of abnormal cells in the skin, inherited traits from our family 
  • Immunosuppression- Problems with the immune system or our body’s immune system body's defence system), 
  • Environmental factors, such as chemical exposure.

However, scientists are still trying to understand all the details.

How does mycosis fungoides appear on the skin?

MF can show up on the skin in different ways. It can occur in several stages, but everyone will not progress through a similar phase. Initially, it might look like red, scaly patches that might itch or bother you. This stage of MF is patch stage.9

Bobjgalindo, Wikimedia Commons

As it progresses, it could become thicker, raised areas called plaques. Sometimes, these plaques might look like lumps or tumours under the skin, and this is called the tumour stage.You may experience discomfort as the skin can sometimes become sensitive in the involved area. It's vital to monitor any changes in your skin and let a doctor know if you notice anything unusual. Some aggressive forms can also present as a rash. 

The importance of a visit to the doctor

Getting a doctor's help is vital if you are worried about any skin lesion or rash suggestive of mycosis fungoides. They know how to look closely and do special tests to find out if it is indeed the disease or something else that looks similar. Once diagnosed, they can guide you on the best ways to manage it and help you feel better. So, if you notice any changes on your skin that worry you, don't hesitate to reach out to a doctor.8

Diagnosis of mycosis fungoides

Diagnosing MF involves a combination of clinical, histopathological and other assessments. Your team of doctors will take several important steps to diagnose MF. 

First, your doctor will carefully listen to all your concerns and will take a detailed history of symptoms, duration and progression. After a thorough examination of your skin, if they suspect MF, they might take a small sample of the affected skin. The biopsy sample is then examined under a microscope for abnormal white blood cells associated with MF.

Additionally, your doctor may advise blood tests and imaging tests to determine if the condition has affected other parts. These steps can help doctors get a clearer picture of what's happening and how to best help you.

What happens in different stages of mycosis fungoides, and how does it affect the body?

MF has different stages in which it affects the body. It mostly stays on the skin in the early stages and might look like red patches or raised areas. It can become thicker plaques or even lumps under the skin as it progresses. In more advanced stages, it might involve lymph nodes inside the body or other organs. This can sometimes lead to more widespread symptoms. But in many cases, especially if caught early, MF can be managed well, and its effects on the body can be minimised with proper medical care.

Treatment and management of mycosis fungoides

MF cannot be cured completely.4 However, it is a slow-growing or ‘indolent’ type of cutaneous lymphoma; MF cases are reported to have a good survival rate.Only a minority is said to progress rapidly and spread to other organs.

Treatment is primarily based on the disease stage, which includes the stage of the skin rash, spread to lymph nodes or other organs. This staging method is an internationally recognised system for cancers called Tumor-Node-Metastasis staging or TNM staging.9 Treating and managing MF involves helping the skin feel better and controlling the condition's progress.

Doctors use various methods to reach these goals. Treatment for MF includes:9 

  • In the early stage-  Cream or light therapies might soothe the skin and reduce the patches
  • In the advanced stage- Your doctor could consider treatments, such as radiation or even stem cell transplantation. 

The main goal is to ease discomfort, slow down the condition's growth, and improve your quality of life. Doctors work with you to find the best treatment plan that suits your needs and helps you live comfortably.

Living with mycosis fungoides 

Living with MF can bring physical and emotional challenges. The skin changes might affect how you feel about your body. It's important to remember that you're not alone – there's support available from doctors, friends, and family. Talking about your feelings and finding ways to manage stress can make a big difference. 

While MF is a long-lasting condition, working closely with healthcare professionals and following their guidance can help you lead a fulfilling life while managing the symptoms.

Advancing mycosis fungoides management strategies

Scientists and doctors are working hard to find better ways to treat MF in the future. They're studying new medicines and therapies to make treatments more effective and gentle. Recent scientific discoveries have given us a better understanding of how this condition works, which helps create targeted treatments.

Researchers are also looking into personalised approaches, meaning treatments tailor-made for each person's unique situation. As we learn more, there's hope that MF will become easier to manage, allowing people to live healthier and more comfortable lives.


Can mycosis fungoides spread to others by contact?

No, it cannot spread to others by contact. Although the name is similar to that of a fungus, it is not a fungus. 

How can I prevent mycosis fungoides?

There are no prevention methods for mycosis fungoides. The best thing you can do for yourself is to regularly check your skin for new rashes or any skin changes and check-up with a doctor.


Mycosis fungoidesis is a type of skin cancer that occurs when certain white blood cells in our body start abnormally multiplying in the skin. This can cause red, scaly patches on the skin that might itch. As it progresses, the patches can become thicker and raised, and sometimes even lumpy under the skin. Doctors can determine the diagnosis by looking closely at the skin and doing special tests. It is important to differentiate it from skin infections and from other aggressive skin cancers that appear rather similar.

While it can be concerning, there are ways to manage mycosis fungoides. Treatment is mostly based on the staging.

Doctors can treat mycosis fungoides with creams, light therapies, and sometimes stronger treatments. It's important to remember that you're not alone if you have mycosis fungoides; there's support available, and with proper care, you can live comfortably and happily.


  1. Mycosis Fungoides (Including Sézary Syndrome) Treatment (PDQ®)–Patient Version - National Cancer Institute [Internet]. www.cancer.gov. 2020. Available from: https://www.cancer.gov/types/lymphoma/patient/mycosis-fungoides-treatment-pdq
  2. Mycosis fungoides | DermNet NZ [Internet]. dermnetnz.org. Available from: https://dermnetnz.org/topics/mycosis-fungoides
  3. Mycosis Fungoides [Internet]. Cutaneous Lymphoma Foundation. Available from: https://www.clfoundation.org/mycosis-fungoides
  4. British Association of Dermatologists [Internet]. www.bad.org.uk. Available from: https://www.bad.org.uk/pils/mycosis-fungoides/
  5. Skin cancer symptoms [Internet]. www.cancerresearchuk.org. [cited 2023 Aug 7]. Available from: https://www.cancerresearchuk.org/about-cancer/skin-cancer/symptoms?gclid=CjwKCAjw_aemBhBLEiwAT98FMtZzTt-pFn4zk4ofGO_seq5XUMLhXE8y_P6_2gxNRbF7WGttdZ3AgRoCmmQQAvD_BwE&gclsrc=aw.ds
  6. Carter D. Cutaneous T cell lymphoma: When a rash is actually cancer [Internet]. MD Anderson Cancer Center. Available from: https://www.mdanderson.org/cancerwise/what-is-mycosis-fungoides--when-a-rash-is-actually-cutaneous-t-cell-lymphoma-cancer.h00-159542112.html
  7. Mycosis fungoides - an overview | ScienceDirect Topics [Internet]. www.sciencedirect.com. [cited 2023 Aug 7]. Available from: https://www.sciencedirect.com/topics/medicine-and-dentistry/mycosis-fungoides
  8. Jonak C, Tittes J, Brunner PM, Guenova E. Mycosis fungoides and Sézary syndrome. J Dtsch Dermatol Ges [Internet]. 2021;19(9):1307–34. Available from: http://dx.doi.org/10.1111/ddg.14610
  9. Mycosis fungoides [Internet]. www.pathologyoutlines.com. Available from: https://www.pathologyoutlines.com/topic/skintumornonmelanocyticmycosisfungoides.html
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Varuni Upamali Fernando

MBBS(Colombo), DipRCpath, CHCCT(UK)

Curent role as Specialty Doctor in Histopathology and previously as Associate Specialist in GI pathology. STEM ambassador and former freelance copywriter for advertising agencies and healthcare institutes.

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