Cutaneous Lymphoma (CL)
Cutaneous lymphomas are a group of T cell and B cell lymphomas which have a highly variable disease course, clinical presentation, and prognosis. Cutaneous T-cell lymphomas (CTCLs) are the most common kind of skin lymphoma. CTCLs often look red and dry like an eczema rash and can affect widespread parts of the body. Cutaneous B-cell lymphomas (CBCLs) more commonly cause lumps in the skin, usually in one or two areas of the body.
Cutaneous T cell lymphomas (CTCLs)
In CTCL, malignant (cancerous) T-cells travel to the upper layers of the skin, causing a rash, which leads to diagnosis. CTCL is sometimes wrongly referred to as a skin cancer because it affects the skin, but this is not a precise use of the term ‘skin cancer’. Skin cancer is the designation for cancers that develop from other, non-lymphoid cells of the skin (epidermal cells, melanocytes, pigment cells). Most CTCLs are indolent (i.e. chronic) lymphomas – non-curable, but treatable and usually not life-threatening.
The two most common types of CTCL are:
- Classic mycosis fungoides (MF): Most common form of CTCL. It is an indolent type, following a slow, chronic course, often over many years or decades, and very often does not spread beyond the skin. Over time, in about 10% of cases, it can progress beyond the skin. Most people will have the classic form of MF, but there are several rarer forms. MF typically presents with red, scaly patches or thickened plaques of skin that often mimic eczema or chronic dermatitis. Progression from limited skin involvement is variable and may be accompanied by tumor formation, ulceration, and exfoliation, complicated by itching and infections. Advanced stages are defined by involvement of lymph nodes, peripheral blood, and internal organs. MF usually occurs in adults over age 50 but affected children have been identified.
- Sézary syndrome (SS): Less common but more aggressive (fast-growing) type of CTCL that is related to MF but presents with very severe itching, total body redness (erythroderma), intense scaling of the skin and frequent hair loss. People with SS often lose large amounts of skin during the night and may find their bedding covered with skin flakes in the morning. They may also feel tired, have a fever and have enlarged lymph nodes. The malignant (cancerous) T cells found in the skin are also seen circulating in the bloodstream. SS is the only type of CTCL that always affects the skin and the blood. The skin may be hot, sore, extremely itchy, occasionally flaking and burning. Oozing of clear fluid from the skin is common. Because much heat is lost through the skin, people often feel cold. Symptoms may be accompanied by changes in nails, hair, or eyelids. SS usually occurs in adults over age 60.
Other forms of CTCL include:
|Primary cutaneous CD30+ lymphoproliferative disorders||There are two main types of these disorders, accounting for almost one-third of all diagnosed CTCLs: lymphomatoid papulosis (LyP) and primary cutaneous anaplastic large-cell lymphoma (PCALCL). In both types, a CD30 protein is found on the surface of the abnormal lymphocytes. Both disorders can be well-managed and have an excellent prognosis: 1. LyP: Presents with self-healing small red-brown bumps and spots on the skin (papules) that come and go. LyP is usually classified as non-malignant or as a CTCL precursor. LyP can occur at any age and affects both genders equally. 2. PCALCL: An indolent type of CTCL, with characteristic features that include single or multiple raised red skin lesions and nodules, which do not typically crust and have a tendency to ulcerate. These lesions may appear anywhere on the body and grow very slowly, so they may be present for a long time before being diagnosed. PCALCL can affect people of all ages, including children, but is most commonly found in adults 45 to 60 years old, and occurs more often in men than women.|
|Subcutaneous panniculitis-like T cell lymphoma (SPTCL)||Rare, slow-growing and can occur at any age. It is slightly more common in women. It starts in the fatty layer of the skin, just below the surface. There may be one or more plaques or nodules, often on the legs. Other more general symptoms may be present, such as fevers, low blood counts and weight loss.|
|Extranodal natural killer T cell lymphoma (ENKTL), nasal type||Rare, aggressive (fast-growing) cancer that can develop in T lymphocytes (T cells) or in natural killer (NK) cells. It is called ‘extranodal’ because it develops in organs or tissues other than the lymph nodes. It typically affects areas in the nose (called ‘nasal type’), most often the nasal passages, but it can also affect the upper part of the throat and the paranasal sinuses. ENKTL may be called ‘extranasal type’ when it affects the skin, testicles, soft tissues, kidneys, brain and/or spinal cord, respiratory tract, gastrointestinal tract, eyes, or adrenal glands. ENKTL, nasal type, is more common in Asia, South America, and Central America than it is in North America. The average age at diagnosis is 60, and it occurs more often in men than women. It is linked to the Epstein-Barr virus (EBV), especially in people of Asian descent.|
|Primary cutaneous peripheral T-cell lymphoma-not otherwise specified||There are three subgroups within this category: 1. Primary cutaneous CD4-positive small/medium T cell lymphoma: A slow-growing lymphoma with a good prognosis (outlook). It usually appears as a single plaque or nodule on the face, neck, or upper torso. 2. Primary cutaneous gamma/delta T-cell lymphoma: A faster-growing type of skin lymphoma that usually occurs in adults. It most commonly shows up as patches and plaques on the arms or legs. Symptoms may also include night sweats, fevers, and weight loss. Some people develop low blood counts and an enlarged liver and spleen. 3. Primary cutaneous CD8-positive aggressive epidermotropic cytotoxic T-cell lymphoma: A faster growing lymphoma that occurs mainly in adults. It appears as widespread spots (papules), plaques and tumours on the skin. Affected areas may ulcerate. It can also affect the lining of the mouth.|
Cutaneous B cell lymphomas (CBCLs)
There are three primary types of CBCL:
- Primary cutaneous follicle centre lymphoma (PCFCL): Most common type of CBCL. PCFCL is indolent (slow-growing) and has a good prognosis. It is most often found on the head, neck, or upper torso. Lesions are pink or red nodules, or slowly-developing tumours. They rarely become open sores or ulcers. Some patients find nodules in many locations on the body, but more often it is a single tumour or small group of nodules.
- Primary cutaneous marginal zone B cell lymphoma (PCMZL): Second most common form of CBCL. PCMZL is indolent (slow-growing) and has a good prognosis. PCMZL is related to a type of lymphoma known as extranodal lymphoma of mucosa-associated lymphoid tissue (MALT) type. Patients find pink or red papules, nodules or, less frequently, tumours. It can occur anywhere on the skin but tends to show up on arms, legs, or torso. This is one of the few skin lymphomas with a known cause. Some people with a MALT lymphoma have evidence of a bacterial infection called Borrelia burgdorferi. People who have this infection will receive treatment with antibiotics first. When there is no infection, treatment is usually with radiotherapy or surgery, particularly if the lymphoma is only in one area.
- Primary cutaneous diffuse large cell lymphoma, leg type (also known as PCLBCL-LT): A rare and more dangerous type of CBCL that looks much different under the microscope, and most of the time is found in the lower legs, more commonly in older women, where it can reach a very significant size. PCLBCL-LT often grows into large tumours that extend deep into the fat of the body, growing quickly and becoming open sores. Unlike slow-growing types of lymphoma, this one has a high likelihood of spreading outside the skin.