Cutaneous Lymphoma (Skin Lymphoma)

What cutaneous lymphoma is

Lymphocytes are white blood cells that patrol the body, including the skin. In cutaneous lymphoma, one family of these cells becomes cancerous and settles in the skin. It is a type of non-Hodgkin lymphoma, but it behaves very differently from lymphomas that start in the lymph nodes: most forms grow over years, not months, and many never spread inside the body.

Doctors divide it by which lymphocyte is involved: T cells or B cells. This matters because the look, treatment and outlook differ.

Cutaneous T-cell vs B-cell lymphoma

Cutaneous T-cell lymphoma types

• Mycosis fungoides: the commonest form. It starts as pink, scaly, slightly wrinkled patches that look like eczema or psoriasis, often for years before diagnosis. Over time some become raised plaques and, in a minority, tumors. See our detailed page on cutaneous T-cell lymphoma.
• Sézary syndrome: rare and aggressive. Nearly all the skin becomes red and itchy (erythroderma), lymph nodes swell, and lymphoma cells circulate in the blood.
• Lymphomatoid papulosis: crops of small bumps that ulcerate and heal on their own over weeks, leaving small scars. It is usually benign in behavior but needs long-term follow-up.
• Primary cutaneous anaplastic large cell lymphoma: one or a few nodules that may ulcerate. It usually stays in the skin and responds well to surgery or radiation.

Cutaneous B-cell lymphoma types

• Primary cutaneous marginal zone lymphoma: red or purple bumps on the arms or trunk. Very slow-growing.
• Primary cutaneous follicle center lymphoma: firm nodules, often on the scalp, forehead or back. Very slow-growing.
• Diffuse large B-cell lymphoma, leg type: fast-growing red or bluish tumors, usually on the lower legs of older adults. This type needs chemotherapy-based treatment.

Symptoms

• Scaly patches that persist or slowly change shape and size
• Itching, sometimes intense
• Raised plaques, lumps or nodules, which may ulcerate
• Widespread redness and peeling in Sézary syndrome
• Hair loss over affected patches
• Swollen lymph nodes in more advanced disease
• Rarely, fever, night sweats or weight loss

Causes and risk factors

The cause is not known. Cutaneous lymphoma is not contagious and is not inherited. It is more common in people over 50 and in men, and mycosis fungoides is more common in Black people in the US. Rare links include long-term immune suppression and, for some B-cell types in Europe, Borrelia infection from tick bites.

Diagnosis

Early cutaneous lymphoma is notoriously hard to diagnose because it looks like common rashes and because early biopsies can look like simple inflammation. Doctors rely on:

1. Skin biopsies, often repeated over time, with immunohistochemistry stains that identify the type of cell
2. T-cell or B-cell receptor gene testing to show that the cells are a single clone
3. Blood tests, including flow cytometry to look for lymphoma cells in the blood
4. A full skin and lymph node examination, with a node biopsy if any are enlarged
5. Imaging (CT or PET-CT) for advanced or aggressive types

Staging for mycosis fungoides uses the TNMB system, which considers how much skin is involved, the lymph nodes, internal organs and blood.

Treatment

Treatment depends on the type and stage. Early, slow-growing disease is controlled rather than cured, and the aim is to clear the skin with the fewest side effects.

Skin-directed treatments

• Strong topical steroid creams
• Topical chemotherapy (mechlorethamine gel) or retinoids
• Phototherapy (narrowband UVB or PUVA)
• Low-dose radiation to individual lesions, or total skin electron beam therapy for widespread disease
• Surgical removal of single B-cell lymphoma nodules

Systemic treatments

Used for advanced or aggressive disease: oral retinoids (bexarotene), interferon, methotrexate, targeted antibodies (mogamulizumab, brentuximab vedotin), histone deacetylase inhibitors, extracorporeal photopheresis for Sézary syndrome, rituximab-based chemotherapy for leg-type B-cell lymphoma, and stem cell transplant in selected cases.

Living with symptoms

Itch control matters a great deal. Daily moisturizers, antihistamines, and treatment of skin infections (more common in damaged skin) improve comfort.

Outlook

Early-stage mycosis fungoides limited to patches and plaques has a life expectancy close to that of the general population. Marginal zone and follicle center B-cell lymphomas also have excellent survival, although new spots often come back. Sézary syndrome, advanced mycosis fungoides and leg-type B-cell lymphoma are more serious and need specialist care at a center experienced in cutaneous lymphoma. Long-term follow-up with a dermatologist is standard for all types.

Frequently asked questions

What does skin lymphoma look like?

T-cell skin lymphoma usually starts as flat, pink to red, scaly patches that look like eczema, often on the buttocks, hips or trunk. On darker skin they may look lighter or darker than surrounding skin. B-cell skin lymphoma usually looks like one or a few smooth, firm, pink, red or purple bumps.

Is cutaneous lymphoma a skin cancer?

It is a cancer that appears in the skin, but it is a blood cancer (a lymphoma), not a skin cancer like melanoma or basal cell carcinoma. It is treated by dermatologists and hematologist-oncologists rather than by the methods used for other skin cancers.

Is cutaneous lymphoma curable?

Some types can be cured, such as single B-cell nodules removed or treated with radiation. Mycosis fungoides is usually treated as a long-term condition that can be kept in remission for many years. Most people with early-stage disease have a normal or near-normal lifespan.

Why does cutaneous lymphoma take so long to diagnose?

Early patches look like eczema, psoriasis or fungal rashes, and early biopsies can look like ordinary inflammation. Many people are diagnosed several years after the rash first appears, after repeated biopsies. A rash that does not respond to standard treatment should be biopsied.

Can cutaneous lymphoma spread?

Most types stay in the skin for many years. A minority of mycosis fungoides cases progress to tumors and spread to lymph nodes, blood or organs. Leg-type B-cell lymphoma and Sézary syndrome are more likely to spread and are treated more intensively from the start.