Cutaneous T-cell lymphoma

The term cutaneous T-cell lymphoma (CTCL) refers to a skin condition in which there is an abnormal neoplastic proliferation of lymphocytes with a ´T´ subtype (thymus-derived). The diagnosis is made by skin biopsy.

Cutaneous T-cell lymphoma includes:

• Mycosis fungoides
• Sézary syndrome
• Follicular cell lymphoma
• T-cell leukaemia

Mycosis fungoides

Mycosis fungoides is a condition in which the skin is infiltrated by patches or lumps composed of white cells called lymphocytes. It is more common in men than women and is very rare in children. Its cause is unknown but in some patients it is associated with a pre-existing contact allergic dermatitis or infection with a retrovirus.

Mycosis fungoides may persist in one stage or slowly progress to another stage.

• Patch stage: at this stage the skin condition is flat. Most often there are oval or ring-shaped pink dry patches on covered skin. They may spontaneously disappear, remain the same size, or slowly enlarge. The skin may be atrophic (thinned), and may or may not itch. The patch stage of mycosis fungoides can be difficult to distinguish from psoriasis, discoid eczema or parapsoriasis.
• Plaque stage: the patches become thickened and may resemble psoriasis. They are usually itchy.
• Tumour stage: large irregular lumps develop from plaques, or de novo. They may ulcerate. At this stage, spread to other organs is more likely than in earlier stages.
• Poikiloderma atrophicans vasculare: an unusual type of mycosis fungoides in which the skin, especially on the trunk, shows areas of thinning, pigmentary change and dilation of the capillaries (telangiectasia).

Sézary syndrome
Sézary syndrome is the name given when T-cell lymphoma affects the skin of the entire body. It is also known as the red man syndrome because the skin is bright red. The skin is also thickened, dry or scaly and usually very itchy. Examination of the blood usually reveals the presence of Sézary cells.

Follicular cell lymphoma

Follicular cell lymphoma is a localised form of cutaneous T-cell lymphoma in which there is a slowly enlarging solitary patch, plaque or tumour in which biopsy shows characteristic lymphomatous change around hair follicles. It is a type of alopecia mucinosa.

Adult T-cell leukaemia
T-cell leukaemia, is a serious blood disease in which there are large numbers of circulating atypical cells. It is caused by a retrovirus infection with human T-lymphotropic virus (HTLV I). It results in skin lesions similar to those found in mycosis fungoides or Sézary syndrome, enlarged lymph glands, high levels of calcium in the blood and bone lesions.

Investigations

The diagnosis of cutaneous T-cell lymphoma is made by a dermatopathologist as there are characteristic microscopic changes seen on skin biopsy. The diagnosis is often delayed for months or years and may require several biopsies, as early cutaneous T-cell lymphoma can be difficult to tell apart from other skin conditions, particularly eczema.

Enlarged lymph nodes may also be biopsied. Cutaneous T-cell lymphoma can cause harmless swelling, known as ´reactive´ or ´dermopathic´ lymphadenopathy, or result in malignant growth in the lymph nodes.

The blood count is normal in most patients with cutaneous T-cell lymphoma, but an elevated white cell count is characteristic of Sézary syndrome.

Patients with advanced cutaneous T-cell lymphoma may have CT or MRI scans to determine whether the disease affects internal organs.

Treatment

Treatment of individual patients varies, and depends on the stage, local expertise and available drugs and equipment. The following may be useful.

• Topical steroids
• UVB Phototherapy
• PUVA Photochemotherapy
• Topical nitrogen mustard
• Chemotherapy
• Localised radiotherapy
• Electron beam radiotherapy
• Interferons
• Oral retinoids
• Photopheresis.

Prognosis

Cutaneous T-cell lymphoma often remains confined to the skin for many years, in some cases the abnormal cells may eventually infiltrate other tissues including blood, lymph nodes, lungs, heart, liver and spleen.

Unlike some other lymphomas, the outlook is generally good. Symptoms can usually be controlled with treatment. However treatment is not curative.