Mycosis fungoides: a review

Mycosis fungoides (MF) is the commonest subtype of cutaneous lymphoma, characterized by the infiltration of malignant T-cell clones into the skin. It accounts for approximately 60% of all cutaneous T-cell lymphoma diagnoses. MF has three distinct clinical stages - patch, plaque and tumour - presenting most commonly on the buttocks, trunk and breast. The presentation often mimics common inflammatory dermatoses such as eczema and psoriasis. Despite numerous theories, the aetiology of MF remains mostly unknown. Since its first description in 1806, diagnosis has remained a challenge and requires careful clinicopathological correlation. Patients may require multiple skin biopsies, especially at the patch stage, to identify the characteristic epidermotropic infiltrates of small-to-medium-sized lymphocytes. First-line management involves skin-directed therapies such as topical corticosteroids and phototherapy. If these are unsuccessful, systemic medications such as interferon-α, oral bexarotene, methotrexate and novel antibody therapies are trialled. MF can also respond to localized radiotherapy, total skin electron beam therapy and haematopoietic stem cell transplantation. Despite being primarily a cutaneous lymphoma, MF can progress to involve other organs. This review provides a comprehensive overview of the epidemiology, clinical features, diagnosis and management of MF.