We describe a previously unreported association of idiopathic retroperitoneal fibrosis with mesenteric, pulmonary and perhaps periarticular fibrotic involvement, and panniculitis resembling Weber-Christian panniculitis. The onset of the disease was uncommon with arthritis. Then, several episodes of migratory panniculitis appeared; biopsy showed septal panniculitis without necrosis of adipose tissue. Considering the patient's anamnesis, it is tempting to speculate that these manifestations all originate from the same mechanism.