These lesions can start as insignificant patches and may remain undiagnosed for up to a decade. Hypopigmentation (when the skin is lighter than normal) of lesions are less common but can be found in children, adolescents and/or dark-skinned individuals.The advanced stage of mycosis fungoides is characterized by generalized erythroderma (red rash covering most of the body) with severe pruritus (itching) and scaling. Itching (Pruritus) is the most commonly reported symptom of people experiencing mycosis fungoides with up to 88% of people reporting varying intensities of pruritus that typically worsens as the disease progresses. Those that experience intense pruritus commonly indicate that it negatively affects their quality of life emotionally, functionally and physically.Mycosis fungoides (MF) and Sézary syndrome (SS) are related conditions with the same type of cancer t-lymphocytes that initially grow in different body compartments. SS cells are mainly found in the blood, whereas MF typically involves the skin. In advanced stages of MF, the cancer cells move from the skin into the blood stream and other organs, and is referred to as  "leukemic mycosis fungoides", :Sézary syndrome preceded by mycosis fungoides", or "secondary mycosis fungoides". Cause
Mycosis fungoides is caused by abnormal white blood cells (T-lymphocytes). These abnormal cells have a preference for localizing and proliferating uncontrolled in the outer layer of the skin (epidermis). The abnormal cells may later involve other organs such as the lymph nodes.
In the tumorous stage a dense infiltrate of medium-sized lymphocytes with cerebriform nuclei expands the dermis. Accurate staging of mycosis fungoides is essential to determine appropriate treatment and prognosis. Staging is based on the tumor, node, metastasis, blood (TNMB) classification proposed by the Mycosis Fungoides Cooperative Group and revised by the International Society for Cutaneous Lymphomas/European Organization of Research and Treatment of Cancer. This staging system examines the extent of skin involvement (T), presence of lymph node (N), visceral disease (M), and presence of Sezary cells in the peripheral blood (B).Most patients with mycosis fungoides have early-stage disease (Stage IA-IIA) at the time of their initial diagnosis. People with early stage disease that is primarily confined to the skin have a favorable prognosis. People with advanced stage (Stage IIB-IVB) are often refractory to treatment and have an unfavorable prognosis. Treatment options for people with advanced stage disease are designed to reduce tumor burden, delay disease progression, and preserve quality of life. Treatment
The most commonly recommended first-line treatment for mycosis fungoides is psoralen plus ultraviolet A (PUVA therapy). PUVA is a photochemotherapy that involves topical or oral administration of the photosensitizing drug psoralen followed by skin exposure to ultraviolet radiation. Systemic treatments of mycosis fungoides often lead to resistance; as such, additional treatment options are often necessary in advanced disease.Other treatments that have been suggested, however, larger and more extensive research is needed to identify effective treatment strategies for this disease.