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 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 corticosteroids, chemotherapy, and radiotherapy.
Signs and symptoms
Typical visible symptoms include rash-like patches, tumors, or lesions. Itching (pruritus) is common, perhaps in 20 percent of patients, but is not universal. The symptoms displayed are progressive, with early stages consisting of lesions presented as scaly patches. These lesions prefer the buttock region. The later stages involve the patches evolving into plaques distributed over the entire body. The advanced stage of mycosis fungoides is characterized by generalized erythroderma, with severe pruritus and scaling.
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.
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).
Peripheral smear will often show buttock cells.
Diagnosis | Staging
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 dermatosis 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 the tumorous stage a dense infiltrate of medium-sized lymphocytes with cerebroid nuclei expands the dermis.
Mycosis fungoides can be treated in a variety of ways. Common treatments include simple sunlight, ultraviolet light (mainly NB-UVB 312 nm), topical steroids, topical and systemic chemotherapies, local superficial radiotherapy, the histone deacetylase inhibitor vorinostat, total skin electron radiation, photopheresis and systemic therapies (e.g. interferons, retinoids, rexinoids) or biological therapies. Treatments are often used in combination.
In the “Stanford technique” of Total skin electron therapy the patient stands about 10 meters from a radiation source, with a large acrylic sheet in between to scatter the electrons across a broad area. Then the patient carefully assumes six different positions. In severe cases that progress to Sézary disease
Stanford University has been pioneering low-dose radiation (1/3 of the standard), followed by stem-cell transplantation without chemo, as a potential cure with promising results.
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.
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). The incidence of mycosis fungoides was seen to be increasing till the year 2000 in the United States, thought to be due to improvements in diagnostics. However, the reported incidence of the disease has since then remained constant, suggesting another unknown reason for the jump seen before 2000.
Mycosis fungoides was first described in 1806 by French dermatologist Jean-Louis-Marc Alibert. The name "mycosis fungoides" is very misleading—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.
Experimental treatments include Resimmune or A-dmDT390-bisFv(UCHT1) which is an anti-T cell immunotoxin in a Phase II clinical trial.
Mogamulizumab (KW-0761) had a phase 3 clinical trial for Relapsed/Refractory CTCL (including mycosis fungoides). After preliminary results on mycosis fungoides in 2017 the US FDA granted it a priority review for CTCL.