Generalized lymphadenopathy mimicking malignant lymph node metastases after interferon-α2b therapy for melanoma.

A patient, who complained of axillary swelling, was diagnosed with malignant melanoma of stage IIb and received adjuvant high-dose interferon-α2b (HDI) therapy for 3 months. Computed tomography demonstrated multiple, generalized lymph node enlargement with high fluorine-18-fluorodeoxyglucose uptake (6.6 of the standardized uptake value) on PET. Histological examination of the axillary lymph node revealed reactive hyperplasia, without evidence of malignant cells. Discontinuation of interferon therapy for 6 weeks resulted in near-complete resolution of the lymphadenopathies. HDI therapy was therefore resumed at a reduced dose and was continued for 25 weeks without recurrence of the lymphadenopathies. HDI therapy is the only adjuvant therapy proven to be effective in malignant melanoma. The release of various additional cytokines is stimulated by interferon, which is responsible for the more common side effects of this therapy. The cytokines are also likely to stimulate helper T cells and induce T-cell sequestration within lymph nodes. These actions are possibly associated with generalized lymph node enlargement in some patients undergoing HDI therapy. The results from the present case indicate that HDI therapy can be safely maintained after confirming the benign nature of the lymphadenopathies that occur during the treatment.