(See also Overview of Lymphoma Overview of Lymphoma Lymphomas are a heterogeneous group of tumors arising in the reticuloendothelial and lymphatic systems. The major types are Hodgkin lymphoma Non-Hodgkin lymphoma See table Comparison of Hodgkin... read more and Non-Hodgkin Lymphomas Non-Hodgkin Lymphomas Non-Hodgkin lymphomas are a heterogeneous group of disorders involving malignant monoclonal proliferation of lymphoid cells in lymphoreticular sites, including lymph nodes, bone marrow, the... read more .)
Mycosis fungoides and Sézary syndrome are the 2 main types of cutaneous T-cell lymphomas. They comprise less than 5% of all lymphoma cases.
Cutaneous T-cell lymphomas are insidious in onset. Patients may initially present with a chronic, pruritic rash that is difficult to diagnose even with biopsies. This prodrome may exist for several years until the diagnosis of cutaneous T-cell lymphoma is finally made.
The lesions of mycosis fungoides are characterized as patches, plaques, or tumor nodules; the nodules often ulcerate and become infected.
In Sézary syndrome, the skin is typically diffusely red with cracking of the palms and soles. Lymphadenopathy is usually mild to moderate. Symptoms are related mostly to the skin, with fevers, night sweats, and unintentional weight loss coming later in the disease course.
Diagnosis of Cutaneous T-cell Lymphomas
Peripheral blood smear and flow cytometry for circulating malignant T-cells (Sézary cells)
For staging, lymph node biopsy and CT of chest, abdomen, and pelvis or FDG-PET (fluorodeoxyglucose-positron emission tomography)
Diagnosis is based on skin biopsy, but histology may be equivocal early in the course because of insufficient quantities of lymphoma cells. The malignant cells are mature CD4+ T cells that may have lost common T-cell markers such as CD7.
Characteristic Pautrier microabscesses are present in the epidermis on skin punch biopsies. In some cases, a leukemic phase called Sézary syndrome is characterized by the appearance of malignant T cells with serpentine nuclei in the peripheral blood. These can be detected on a routine Wright-stained smear or by flow cytometry.
After diagnosis, stage is determined to guide therapy. The commonly used ISCL/EORTC (International Society of Cutaneous Lymphomas/European Organization of Research and Treatment of Cancer) staging system incorporates physical examination findings, histopathology results, and results of imaging tests (1, 2) Diagnosis references Mycosis fungoides and Sézary syndrome are uncommon chronic T-cell non-Hodgkin lymphomas primarily affecting the skin and occasionally the lymph nodes. (See also Overview of Lymphoma and Non-Hodgkin... read more .
1. Olsen EA: Evaluation, diagnosis, and staging of cutaneous lymphoma. Dermatol Clin 33(4):643–654, 2015. doi: 10.1016/j.det.2015.06.001
2. Willemze R, Cerroni L, Kempf W, et al: The 2018 update of the WHO-EORTC classification for primary cutaneous lymphomas. Blood133 (16):1703–1714, 2019. doi: 10.1182/blood-2018-11-881268
Prognosis for Cutaneous T-cell Lymphomas
Most patients are > 50 years at diagnosis. Survival rates vary markedly depending on stage at diagnosis. Patients who receive treatment for stage IA disease have a life expectancy analogous to that of similar people without mycosis fungoides. Patients with stage II disease have a median survival > 5 years, while those diagnosed with stage IV disease survive for just over 2 years.
Treatment of Cutaneous T-cell Lymphomas
Radiation therapy, topical chemotherapy, phototherapy, or topical corticosteroids
Sometimes systemic chemotherapy
Treatment of Sezary syndrome and mycosis fungoides is similar. Treatments can be divided into
Skin-directed (topical chemotherapy, phototherapy, retinoids, radiation therapy)
Chemotherapy (traditional drugs and histone deacetylase [HDAC] inhibitors)
Patients are managed by a team of dermatologists, radiation oncologists, and hematology/oncology specialists. Skin-directed therapies are used first and are often effective for years. As lesions become more resistant, or in patients with Sezary syndrome, systemic therapies are used. Lesions may become infected, and the clinician must always consider an infectious cause for any skin flare.
Electron beam radiation therapy, in which most of the energy is absorbed in the first 5 to 10 mm of tissue, and topical nitrogen mustard have proved highly effective. Plaques may also be treated with sunlight and topical corticosteroids.
Systemic treatment with alkylating drugs and folic acid antagonists produces transient tumor regression, but systemic treatment is primarily used when other therapies have failed, after relapse, or in patients with documented extranodal or extracutaneous disease. Newer drugs include HDAC inhibitors given IV or orally. Extracorporeal photophoresis with a chemosensitive drug has shown modest success.
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