Primary cutaneous T-cell lymphoma (mycosis fungoides and Sézary syndrome): A practical compartment-based review

Primary cutaneous lymphomas are a heterogeneous group of lymphoid neoplasms with predominant skin involvement, among which mycosis fungoides (MF) and Sézary syndrome (SS) are the most frequent and clinically challenging entities. This narrative review provides a multidisciplinary, compartment-oriented approach to the diagnosis, staging and management of MF/SS. We summarize the therapeutic principles across the disease continuum, from early-stage, skin-directed management to advanced-stage systemic therapy, including oral retinoids, methotrexate, extracorporeal photopheresis, mogamulizumab, brentuximab vedotin, chemotherapy and allogeneic stem-cell transplantation. We also address large-cell transformation, response assessment, follow-up strategies, and practical issues surrounding treatment maintenance, spacing and discontinuation in a chronic, relapsing disease. Finally, we highlight the importance of supportive care, particularly pruritus control and palliative integration when no further effective options remain, and provide pragmatic algorithms to facilitate real-world clinical decision-making.