Lymphomatoid Papulosis, Type B

Four pink nodules appeared in a linear array on the proximal extensor right forearm of a 77-year-old man. The asymptomatic lesions, which ranged from 0.5 to 1.0 cm in diameter, had been present for 2 months.

Robert P. Blereau, MD of Morgan City, La, reports that 28 years earlier, the patient had mycosis fungoides, poikilodermatous plaque–type, of the feet, right lower abdomen, right lower thigh, and right buttock. After treatment with superficial irradiation, the disease resolved completely. There have been no recurrences.

Excisional biopsy of the largest of the 4 lesions revealed malignant lymphoma, pleomorphic large cell–type. When the patient returned for biopsy suture removal 1 week later, it was noted that the 3 remaining lesions had vanished spontaneously.

A chronic lymphocyte/leukemia/ lymphoma profile with immunophenotyping by flow cytometry showed no monoclonal B-cell populations and no loss or aberrant expression of the pan T antigens that suggests a neoplastic T-cell process. CT scans of the neck, chest, abdomen, and pelvis revealed no lymphadenopathy, splenomegaly, or hepatomegaly.

Cutaneous non-Hodgkin lymphomas are classified into many T-cell and B-cell variants; lymphomatoid papulosis and large-plaque parapsoriasis are placed in a category of their own. They often contain monoclonal T cells, but their behavior is unpredictable. Lesions of lymphomatoid papulosis, type B, may regress spontaneously after several weeks or months, and a few or many hundreds of lesions may develop during each exacerbation. Lesions can become necrotic, crusted, and ulcerated. The clinical course may extend over decades. This condition occurs primarily in women, whereas T-cell lymphoma is more prevalent in men and follows an indolent course.

Lymphomatoid papulosis is categorized as type A (histocytic) or type B (lymphocytic) based on histologic characteristics; many patients exhibit features of both types. The clinical course of the disease is benign and chronic. Lesions persist for a few weeks then involute, only to recur over months to years. Between 5% and 20% progress to full-fledged lymphoma (mycosis fungoides, T-immunoblastic lymphoma, or Hodgkin disease).

There has been no recurrence in this patient since the large lesion was excised and the other 3 regressed.

References:

FOR MORE INFORMATION:

• Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 3rd ed. St Louis: Mosby; 1996:678.

• Weedon D. Skin Pathology. Edinburgh: Churchill Livingstone; 1997:902-904.