Leukemic phase of follicular lymphoma after treatment with etanercept in a patient with psoriasis.

Etanercept, a fully human soluble recombinant p75 tumor necrosis factor (TNF) receptor that blocks the binding of TNF to cell surface receptors, is approved for the treatment of psoriatic arthritis and other rheumatic conditions in the US and Europe. Ever since the introduction of anti-TNF treatment in patients with inflammatory autoimmune diseases, there have been concerns about a possible tumor-promoting effect of such a measure. We report a rare case of leukemic phase of follicular lymphoma in a 62-year-old man with moderate-to-severe plaque psoriasis receiving long-term treatment with etanercept for 3 years. Although the association is intriguing, no causal relationship is suggested.