Background: Therapeutic biologic agents are uncommonly associated with lymphoma.
Case presentation: We report a patient with psoriasis treated with the biologic agents efalizumab (Raptiva) and etanercept (Enbrel), who developed painless lymphadenopathy with peripheral lymphocytosis during treatment, simulating a non-Hodgkin lymphoma clinically and pathologically. Lymphocytosis and lymphadenopathy spontaneously remitted following cessation of etanercept therapy and have not recurred.
Conclusion: Distinction between clinically benign lymphoid proliferations related to anti-psoriasis therapy and malignant lymphoma avoids the unnecessary use of anti-lymphoma chemotherapy.