Lymphomatoid papulosis

What is lymphomatoid papulosis?

Lymphomatoid papulosis is a rare skin disorder that is characterised by crops of self-healing skin lesions that look cancerous under the microscope but are actually benign. Lesions contain unusual cells that are similar to those found in some lymphomas.

Although most cases of lymphomatoid papulosis are benign, 10–20% of patients may have an associated lymphoma before, at the same time as, or after the diagnosis of lymphomatoid papulosis. 

What causes lymphomatoid papulosis and who gets it?

The cause of lymphomatoid papulosis is unknown but it is associated with a proliferation of atypical T-cell lymphocytes. The estimated incidence is 1.2–1.9 cases per million population so it is a rare disease. It may affect people of all races, sex and age but is less often seen in black-skinned people.

What are the signs and symptoms?

Most patients present with multiple skin papules that may occur anywhere on the body but most often affect the chest, stomach, back, arms and legs. The papules appear in crops and can be mildly itchy. They are quite variable in appearance. They may develop into blood- or pus-filled blisters that break and form a crusty sore before healing completely. Lesions spontaneously heal with or without scarring within 2–8 weeks of appearing.

The number of lesions present can vary from one to hundreds. Crops of lesions come and go over many years.

Lymphomatoid papulosis

Lymphomatoid papulosis

How is the diagnosis made?

The diagnosis must be made by a skin biopsy, sometimes repeated on several occasions. Lymphomatoid papulosis is sometimes confused with acute pityriasis lichenoides and several other skin conditions.

Four histopathologic variants have been described: Type A, Type B, Type C and Type D. Some patients have more than one type of lesion. Specific tests evaluate the types of T-cell lymphocytes in the infiltrate: CD30+ cells are characteristic of lymphomatoid papulosis.

What treatment is available?

The following treatments are used to hasten the healing of lymphomatoid papulosis lesions or suppress the disease.

• Topical steroids
• Intralesional steroid
• Phototherapy (UVB or PUVA)
• Anti-inflammatory agents such as tetracycline antibiotics
• Methotrexate: the response rate is reported to be 75% to doses of 10–30 mg per week, but the disease may relapse.

What is the outlook for lymphomatoid papulosis?

There is no cure for lymphomatoid papulosis. It often lasts for years, over which time patients need to regularly see their doctor to pick up any changes that may signal early lymphoma. 

Other forms of lymphoma have been reported to follow lymphomatoid papulosis in 4–25% patients, so long term follow-up is recommended. These include:

• T-cell lymphoma including mycosis fungoides and CD30+ anaplastic large-cell lymphoma
• B-cell lymphoma
• Hodgkin lymphoma.