Mycosis fungoides
Mycosis fungoides (MF) is the most prevalent form of cutaneous T-cell lymphoma (CTCL), primarily affecting the skin. Named for the mushroom-like skin lesions observed in early patients, this low-grade lymphoma typically progresses slowly and often remains localized to the skin. In some cases, approximately 10% of patients may experience progression to lymph nodes and internal organs over time. The exact cause of MF is unknown, although there are reported genetic changes in certain chromosomes, and exposure to Agent Orange among Vietnam War veterans may be a risk factor, though a direct cause-effect relationship has not been established.
The disease manifests in four stages, each characterized by distinct skin symptoms, and it is diagnosed through skin biopsies and laboratory tests. While there is currently no cure, treatments can include skin-directed therapies like ultraviolet light exposure and topical medications, as well as systemic treatments for more advanced cases. The prognosis varies widely; most patients diagnosed early can expect a normal life expectancy, while those with advanced disease may have a shorter survival rate. Overall, understanding mycosis fungoides is crucial for early diagnosis and management, allowing many patients to lead normal lives despite their condition.
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Mycosis fungoides
ALSO KNOWN AS: MF, Cutaneous T-cell lymphoma (CTCL), cutaneous lymphoma, Alibert-Bazin syndrome, granuloma fungoides
RELATED CONDITIONS: Sézary syndrome (SS), lymphomatoid papulosis (LyP), cutaneous anaplastic large-cell lymphoma, adult T-cell leukemia/lymphoma, peripheral T-cell lymphoma, lymphomatoid granulomatosis, granulomatous slack skin disease, pagetoid reticulosis
DEFINITION: Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma (CTCL). Mycosis fungoides was named after the mushroom-like skin tumors noted in the first patient diagnosed with the condition. A low-grade lymphoma that primarily affects the skin, it generally has a slow course and often remains confined to the skin. Over time, in only about 10 percent of the cases, it slowly progresses to the lymph nodes and internal organs such as the liver, lungs, and bone marrow.
Risk factors: The cause of mycosis fungoides is unknown. There is a tendency for individuals with mycosis fungoides to have DNA additions in parts of chromosomes 7 and 17 and loss of DNA from parts of chromosomes 9 and 10. Still, it is unclear if or how these genetic changes contribute to the condition. There is no supportive research indicating that this is a hereditary disease. Exposure to Agent Orange may be a for developing mycosis fungoides for veterans of the Vietnam War, but no direct cause-effect relationship has been established.
Etiology and the disease process: Mycosis fungoides is a particular variant of lymphoma with major involvement of the skin as well as hilar and mediastinal lymphadenopathy. It is associated with reticular nodular pulmonary lesions and is often complicated by pneumonia, primarily caused by Staphylococcus aureus or Pseudomonas aeruginosa. The condition is not contagious. It is not an infection, and no infectious agents are known to cause the disease. Research has been conducted investigating the role of viruses, but the results are inconclusive.
Incidence: The annual incidence of mycosis fungoides in the United States is 3.6 new cases per million people, comprising 70 percent of cutaneous T-cell lymphomas. It affects men twice as often as women. Mycosis fungoides can begin at any age, but the most common age of onset is fifty. Black Americans are more likely to contract the disease than White or Asian Americans.
Symptoms: Mycosis fungoides progresses through four stages, which are defined by the skin symptoms, including the patch phase, skin tumors phase, skin redness stage, and lymph node stage, where mycosis fungoides begins to spread or metastasize, usually first to the lymph nodes, then to the liver, lungs, or bone marrow.
Screening and diagnosis: Typically, it takes about six years from the onset of symptoms to the diagnosis of mycosis fungoides. Confusion with other conditions is common. A skin sample, known as a skin biopsy, is usually performed. Other laboratory tests can help determine the progression of the cancer. There is no cure for mycosis fungoides, so long-term survival depends on early diagnosis and treatment.
Treatment and therapy: Treatments are directed at either the skin or the entire body (systemic therapy). Skin-directed treatments include ultraviolet light (psoralen and ultraviolet A, or PUVA, UVB, narrow-band UVB), topical steroids, topical chemotherapies (nitrogen mustard, carmustine), topical retinoids, local radiation to single lesions, or total skin electron beam (TSEB). Systemic treatments include oral retinoids, photopheresis, photochemotherapy (also known as PUVA), fusion proteins, interferon, systemic (most commonly cyclophosphamide, doxorubicin, vincristine, and prednisone), and orphan drugs such as bexarotene (Targretin). These treatments may be prescribed alone or in combination.
Prognosis, prevention, and outcomes: The course of mycosis fungoides is unpredictable, as some patients will progress slowly, some will progress rapidly, and some will not progress at all. Most patients experience only skin symptoms without serious complications. About 10 percent experience progressive disease with lymph node involvement or spread to the liver, lungs, or bone marrow.
Most patients live normal lives while they treat their disease; some can remain in for long periods. Although there is no known cure for mycosis fungoides, research indicates that 95 percent of patients diagnosed with early-stage mycosis fungoides (about 70 percent of patients) will have a normal life expectancy. Those diagnosed in later stages of the disease have an estimated survival of three to four years.
Bibliography
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"Mycosis Fungoides." Medline Plus, 17 May 2021, medlineplus.gov/genetics/condition/mycosis-fungoides. Accessed 20 June 2024.
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