A 22 year old female patient presented with fever, night sweats, weight loss and hepatomegaly associated with elevated inflammatory parameters and liver enzymes. Computer tomography revealed a mass located between the inferior vena cava and the psoas muscle as well as enlarged celiac, retroperitoneal and retrocaval lymph nodes. Biopsies of the retrocaval mass led to the diagnosis of retroperitoneal fibrosis. Within a few days of treatment with corticosteroids clinical presentation improved and imaging studies detected complete regression of the retrocaval mass after 6 months.