Cutaneous lymphoma is a rare subtype of non-Hodgkin lymphoma that starts in the skin. It is not classified as a skin cancer because the cancer cells originate in white blood cells called lymphocytes, whereas skin cancers develop from other non-lymphoid cells.
The two main types of lymphocytes are B-cells, which produce antibodies that attack invading bacteria, viruses, and toxins, and T-cells, which destroy the body’s own cells that have been taken over by viruses or become cancerous. Both types of lymphocytes can develop into cutaneous lymphoma, but T-cell cutaneous lymphoma (CTCL) is more common than B-cell cutaneous lymphoma (CBCL). Both types of lymphoma can affect the skin, lymph nodes, peripheral blood, and internal organs.
Cutaneous T-Cell Lymphomas
In CTCL, malignant (cancerous) T-cells travel to the upper layers of the skin. The most common signs of the disease are patchy, scaly, red lesions or thickened plaques of skin that look like eczema or chronic dermatitis. Because they can be confused with other skin conditions, doctors usually take several biopsies of the lesions to confirm the diagnosis.
Most CTCLs are chronic, meaning that they are treatable, but not curable. They are usually not life threatening. The two most common types of CTCL are mycosis fungoides and Sézary syndrome.
Cutaneous B-Cell Lymphomas
CBCLs comprise approximately 20 to 25 percent of all primary cutaneous lymphomas. Unlike CTCLs, CBCLs usually develop in the second layer of skin, called the dermis, and manifest as smooth, red lumps or nodules. There are four types of CBCL: primary cutaneous follicle center lymphoma; primary cutaneous marginal zone B-cell lymphoma; primary cutaneous diffuse large B-cell lymphoma, leg-type; and primary cutaneous diffuse large B-cell lymphoma, other.
Although these lymphomas are slow growing, relapse is much more common with CBCLs than CTCLs, as nearly 50 percent of patients experience recurrence after an initial complete response to treatment. Still, CBCL rarely develops into a disease that affects other areas of the body and the prognosis is usually very good.
As for many cancers, treatment depends on the symptoms, stage of the disease, and personal health profile. In the case of cutaneous lymphoma, it also depends on whether the disease is CTCL or CBCL, and, which other treatments may have been used prior. It is also common for cutaneous lymphoma patients to need to alter their treatment approach if they stop responding to that treatment.
Treatment can be directed to the skin, by way of skin-directed treatments, or it can involve the entire body via systemic treatments. Sometimes patients undergo a combination of both skin-directed and systemic treatments.
For many early-stage skin lymphomas, skin-directed therapy, such as phototherapy, is the first line of treatment. Phototherapy uses ultraviolet A or B light to kill cancer cells on the skin. When targeting early-stage lymphomas, topical medicines, such as steroids, retinoids, and chemotherapy, limit side effects by localizing the therapy to a specific area of the body. Additionally, unlike traditional high-energy radiation, electron beam radiation can be used to penetrate only as far as the skin while causing little damage to surrounding organs and tissues to treat early cutaneous lymphomas.
For more advanced or faster growing lymphomas, systemic treatments are generally used, which are administered orally, intravenously, and subcutaneously. Systematic therapies – including oral retinoids, oral chemo, photopheresis, targeted therapies, and biologic therapies – are designed to affect cancer cells all over the body.
Targeted therapies involve agents that attack cancer cells more specifically, thereby affecting fewer normal, healthy cells and reducing side effects to the body. Biologic therapies are a specific type of systematic targeted therapy in which the body’s cells are employed to attack the cancer. One such therapy, immunotherapy, activates the body’s own immune system to destroy cancer cells, when effective. Monoclonal antibody therapy, a type of immunotherapy, has been used to treat advanced cutaneous lymphoma.
Treatment may also include intravenous chemotherapy or radiation. In rare circumstances, a bone marrow or stem cell transplant may be considered as a treatment option for patients with advanced disease.