Cutaneous T-Cell Lymphoma and Cutaneous B-Cell Lymphoma
Summary of Key Points
Incidence
• Cutaneous lymphomas represent 3.9% of non-Hodgkin lymphomas.
• The annual incidence of cutaneous T-cell lymphoma (CTCL) in the United States is approximately 9.6 cases per 1 million population with a median age of 60 years at initial presentation.
• CTCL accounts for up to 71% and cutaneous B-cell lymphoma (CBCL) accounts for up to 29% of all cutaneous lymphomas.
Biological Characteristics
• CTCL may be indolent as in mycosis fungoides (MF) or aggressive as in Sézary syndrome (SS).
• The malignant T cells in MF/SS are characterized by a CD4+ T-helper (Th)/memory cell phenotype with frequent loss of CD7 and/or CD26 and the expression of skin homing markers such as CLA, CCR4, and CCR10. MF/SS demonstrate an altered immune biology and the accumulation of cytogenetic abnormalities during disease progression with a predominant Th2 cytokine profile in advanced stages.
• Primary CBCLs such as cutaneous follicle center lymphoma have failed to show similar alterations compared with their nodal counterpart. The prognosis of both primary cutaneous follicle center lymphoma and cutaneous marginal zone lymphoma is usually excellent.
• The gene expression profile of primary cutaneous large B-cell lymphoma, leg type, is similar to that of nodal diffuse large B-cell lymphoma (DLBCL) arising from germinal center or post–germinal center–activated B cells with constitutive nuclear factor–κB (NF-κB) pathway activation and strong expression of the IRF4/MUM1 transcription factor and carries a worse prognosis.
Staging Evaluation
• All patients with cutaneous lymphoma should initially be seen and co-managed by a multidisciplinary cutaneous lymphoma team consisting of members from dermatology and oncology with the support of other health care professionals such as radiation oncologists, pathologists, and clinical psychologists.
• Routine evaluation should include complete physical examination, complete blood cell count with differential, and chemistry panel with lactate dehydrogenase (LDH) level, skin biopsy for histology, immunophenotyping and gene rearrangement studies, and lymph node biopsies in cases with enlarged nodes at presentation.
• Imaging studies and flow cytometry panel of peripheral blood should be reserved for patients with clinical and laboratory findings suggestive of systemic disease and/or prominent lymphadenopathy. Bone marrow biopsy is a consideration in advanced-stage disease. Histopathological and molecular results should be correlated with clinical findings and patients classified according to the World Health Organization/European Organization of Research and Treatment of Cancer (WHO/EORTC) consensus classification.
Therapy
• Early-stage MF usually responds well to skin-directed therapies such as phototherapy, radiation, topical nitrogen mustard, retinoid, or corticosteroid skin creams.
• Treatment for patients with advanced stages of MF or SS generally requires systemic therapies, including biological or immune therapies, histone deacetylase inhibitors, conventional chemotherapeutic agents, or combinations of these agents.
