Lymphoma, Cutaneous T-Cell

Key Features

Essentials of Diagnosis

• Localized or generalized erythematous patches or scaly plaques

• Sometimes associated with pruritus, lymphadenopathy

• Distinctive histology

General Considerations

• A cutaneous T cell lymphoma that begins on the skin and may remain there for years or decades (so-called mycosis fungoides)

• Certain medications (including selective serotonin reuptake inhibitors) and photoallergy may produce eruptions clinically and histologically identical to those of mycosis fungoides, so this possibility must always be considered

• Lymph node enlargement may be due to benign expansion of the node (dermatopathic lymphadenopathy) or by specific involvement with mycosis fungoides

Clinical Findings

Symptoms and Signs

• Localized or generalized erythematous patches or plaques, usually on the trunk

• Plaques are almost always over 5 cm in diameter

• Pruritus is a frequent complaint and can be severe

• The lesions often begin as nondescript patches, and it is not unusual for the patient to have skin lesions for more than a decade before the diagnosis can be confirmed

• Follicular involvement with hair loss is characteristic of mycosis fungoides

• In more advanced cases, tumors appear

• Local or diffuse lymphadenopathy may be due to

  • Benign expansion (dermatopathic lymphadenopathy)

  • Involvement with mycosis fungoides

Differential Diagnosis

• Psoriasis

• Drug eruption

• Photoallergy

• Atopic dermatitis (eczema)

• Syphilis

• Tinea corporis (body ringworm)

Diagnosis

Laboratory Tests

• Circulating malignant T cells (Sézary cells) can be detected in the blood (T cell gene rearrangement test)

• Eosinophilia may be present

Diagnostic Procedures

• Diagnosis is based on skin biopsy though numerous biopsies may be required before the diagnosis can be confirmed

Treatment

Medications

• The treatment is complex

• Skin-directed therapies are used initially, including

  • Topical corticosteroids

  • Topical mechlorethamine

  • Bexarotene gel

  • UV phototherapy

• If the disease progresses, the following may be used:

  • PUVA plus retinoids

  • PUVA plus interferon

  • Extracorporeal photophoresis

  • Bexarotene

  • Histone deacetylase inhibitors (romidepsin or vorinostat)

  • Targeted immunomodulators (brentuximab, mogamulizumab)

  • Total skin electron beam therapy

Outcome

Complications

• Overly aggressive treatment may lead to complications and premature demise

Prognosis

• Usually slowly progressive (over decades)

• Prognosis is better in patients with patch or plaque stage disease and worse in patients with erythroderma, tumors, and lymphadenopathy

• Survival is not reduced in patients with limited patch disease

• Elderly patients with limited patch and plaque stage disease commonly die of other causes

When to Refer

• All patients with suspected or proven diagnosis

References