Inflammatory pseudotumor of intra-abdominal lymph nodes manifesting as recurrent fever of unknown origin: a case report. A 27-year-old man presented with a 7-month history of debilitating recurrent fever and weight loss. Extensive clinical evaluation led to the discovery of splenomegaly and retroperitoneal lymphadenopathy. The patient underwent splenectomy as well as liver and lymph node biopsy. Histologic examination of the lymph nodes, but not the liver and spleen, revealed inflammatory pseudotumor of lymph nodes. The patient has remained asymptomatic for more than 3 years following the surgical procedure despite the absence of further intervention. Inflammatory pseudotumor of lymph nodes should be considered in the differential evaluation of prolonged or relapsing fever of unknown etiology. 