Mycosis fungoides and variants

Mycosis fungoides (MF) is the most common type of cutaneous T-cell lymphoma (CTCL), a group of non-Hodgkin lymphomas that primarily affect the skin. In mycosis fungoides, malignant T-lymphocytes (a type of white blood cell) accumulate in the skin, causing various lesions that typically progress through distinct clinical stages. The disease predominantly affects the skin but can eventually involve lymph nodes, blood, and internal organs in advanced stages. The classic presentation of mycosis fungoides evolves through three clinical phases: the patch stage, characterized by flat, scaly, often erythematous (reddish) patches that may resemble eczema or psoriasis; the plaque stage, with raised, thickened, and sometimes itchy lesions; and the tumor stage, featuring larger nodular growths that may ulcerate. Variants of mycosis fungoides include folliculotropic (pilotropic) mycosis fungoides, pagetoid reticulosis (Woringer-Kolopp disease), and granulomatous slack skin. Folliculotropic MF involves hair follicles and often presents on the head and neck with follicular papules, alopecia, and sometimes mucinorrhea. Pagetoid reticulosis is a localized variant presenting as a single psoriasis-like plaque, usually on an extremity, and carries an excellent prognosis. Granulomatous slack skin is an extremely rare variant characterized by the slow development of pendulous, lax skin folds in intertriginous areas. Mycosis fungoides typically follows an indolent course, particularly in early stages, and many patients live for years with skin-limited disease. Treatment is stage-dependent and includes skin-directed therapies such as topical corticosteroids, phototherapy (PUVA or narrowband UVB), topical nitrogen mustard (mechlorethamine), and localized radiation therapy for early-stage disease. For more advanced or refractory disease, systemic therapies may be employed, including retinoids (bexarotene), interferon-alpha, histone deacetylase inhibitors (vorinostat, romidepsin), monoclonal antibodies (mogamulizumab, brentuximab vedotin), extracorporeal photopheresis, and systemic chemotherapy. Allogeneic stem cell transplantation may be considered in select younger patients with advanced disease. Prognosis varies significantly by stage, with early-stage patients having near-normal life expectancy, while advanced-stage disease carries a significantly reduced survival.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Mycosis fungoides and variants