Mycosis fungoides, also known as Alibert-Bazin syndrome or granuloma fungoides, is the most common form of cutaneous T-cell lymphoma. It generally affects the skin, but may progress internally over time. Symptoms include rash, tumors, skin lesions, and itchy skin.
While the cause remains unclear, most cases are not genetic or hereditary. Most cases are in people over 20 years of age, and it is more common in men than women. Treatment options include sunlight exposure, ultraviolet light, topical steroids, chemotherapy, and radiation.
History
Mycosis fungoides was first described in 1806 by French dermatologist Jean-Louis-Marc Alibert. The name mycosis fungoides is very misleadingâ€"it loosely means "mushroom-like fungal disease". The disease, however, is not a fungal infection but rather a type of non-Hodgkin's lymphoma. It was so named because Alibert described the skin tumors of a severe case as having a mushroom-like appearance.
Epidemiology
It is rare for the disease to appear before age 20, and it appears to be noticeably more common in males than females, especially over the age of 50, where the incidence of the disease (the risk per person in the population) does increase. The average age of onset is between 45 and 55 years of age for patients with patch and plaque disease only, but is over 60 for patients who present with tumours, erythroderma (red skin) or a leukemic form (the Sézary syndrome).
Origins and causes
The cause of mycosis fungoides is unknown, but it is not believed to be hereditary or genetic in the vast majority of cases. One incident has been reported of a possible genetic link. It is not contagious.
The disease is an unusual expression of CD4 T cells, a part of the immune system. These T cells are skin-associated, meaning that they biochemically and biologically are most related to the skin, in a dynamic manner. Mycosis fungoides is the most common type of cutaneous T-cell lymphoma (CTCL), but there are many other types of CTCL that have nothing to do with mycosis fungoides and these disorders are treated differently.
Symptoms, diagnosis, and stages
Typical visible symptoms include rash-like patches, tumors, or lesions. Itching (pruritus) is common, perhaps in 20 percent of patients, and is not universal.
Diagnosis is sometimes difficult because the early phases of the disease often resemble eczema or even psoriasis. As with any serious disease, it is advisable to pursue the opinion of a medical professional if a case is suspected. Diagnosis is generally accomplished through a skin biopsy. Several biopsies are recommended, to be more certain of the diagnosis. The diagnosis is made through a combination of the clinical picture and examination, and is confirmed by biopsy.
To stage the disease, various tests may be ordered, to assess nodes, blood and internal organs, but most patients present with disease apparently confined to the skin, as patches (flat spots) and plaques (slightly raised or 'wrinkled' spots).
Traditionally, mycosis fungoides has been divided into three stages: premycotic, mycotic and tumorous. The premycotic stage clinically presents as an erythematous (red), itchy, scaly lesion. Microscopic appearance is non-diagnostic and represented by chronic nonspecific dermatisis associated with psoriasiform changes in epidermis.
In the mycotic stage, infiltrative plaques appear and biopsy shows a polymorphous inflammatory infiltrate in the dermis that contains small numbers of frankly atypical lymphoid cells. These cells may line up individually along the epidermal basal layer. The latter finding if unaccompanied by spongiosis is highly suggestive of mycosis fungoides. In tumorous stage, dense infiltrate of medium sized lymphocytes with cerebroid nuclei, expands the dermis.
Treatments
Mycosis fungoides can be treated in a variety of ways.
If treatment is successful the disease can go into a non-progressing state with clinically clear examination and various tests. This is called remission; it can last indefinitely. Treatments may also cause disease not to progress, while still present, and this is called stable disease; it may last indefinitely but is a more serious situation. Disease may also progress, to involve nodes, blood and internal organs, or transform into a higher-grade lymphoma.
Common treatments include simple sunlight, ultraviolet light, topical steroids, topical and systemic chemotherapies, local superficial radiotherapy, the histone deacetylase inhibitor vorinostat, total skin electron beam radiation, photopheresis and systemic therapies (e.g. interferons, retinoids, rexinoids) or biological therapies. Treatments are often used in combination.
Selection of treatments typically depends on patient preference and access to therapies, as well as recommendations by physicians, the stage of the disease, established resistance to prior therapies, allergies of the patient, clinical evidence of a positive benefit:risk ratio, and so on.
It is incurable, but many patients experience prolonged periods of disease-control. Quality of life is a major objective, in addition to cure, and maximizing periods of remission or stable disease, while minimizing treatments and toxicities, are two central concerns in clinical care.
In 2010, the U.S. Food and Drug Administration granted orphan drug designation for naloxone lotion, a topical opioid receptor competitive antagonist used as a treatment for pruritus in cutaneous T-cell lymphoma.
Experimental treatments include Resimmune® or A-dmDT390-bisFv(UCHT1) which is an anti-T cell immunotoxin in a Phase II clinical trial.