Cutaneous T-cell Lymphomas

Cutaneous T-cell lymphomas comprise a group of lymphatic malignancies that occur primarily in the skin. They represent the commonest type of T-cell lymphomas in adults and the second most common form of extranodal non-Hodgkin's lymphoma. CTCL are characterized by heterogeneous clinical, histological, immunological, and molecular features. The most common type is mycosis fungoides and its leukemic variant, Sézary syndrome. The pathogenesis of CTCL remains obscure; long-term antigen stimulation is thought, through cytokine networks, to induce an inflammatory response with T-cell proliferation, leading to a clonal malignant T-cell with continuous expansion. The standard of care for CTCL remains to be defined and skin directed therapy is usually employed in disease localized to the skin and multi-agent chemotherapy and more aggressive treatment are usually reserved for advanced cases. In some aggressive subtypes of CTCLs, such as primary cutaneous gamma/delta T-cell lymphoma and primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma, more aggressive treatment including bone marrow transplantation should be considered early. Current prognostic models for more common subtypes of CTCL have limitations as well and up to 30% of such patients progress and need aggressive treatment as well. In the past decade significant advances were made in understanding the biology, in diagnostic methods, prognostic schemes, and treatment paradigms for CTCL including the development of multiple novel small molecule therapeutics, monoclonal antibodies, phototherapy, radiation, immunotherapy, and cellular therapy approaches. The aim of this Research Topic is to describe the current and emerging paradigms in understanding biology and clinical management of patients with CTCL.