Systemic idiopathic fibrosis: Report of a case of the concomitant occurrence of retractile mesenteritis and retroperitoneal fibrosis

A case of the concomitant occurrence of retractile mesenteritis and retroperitoneal fibrosis is reported. The pathology and pathogenesis of the two conditions appear to be identical. It is therefore suggested that the two disease processes, along with mediastinal fibrosis, sclerosing cholangitis, Riedel's thyroiditis, and pseudotumor of the orbit are manifestations of the same systemic disease of fibrofatty connective tissue occurring in different locations. The etiology of systemic idiopathic fibrosis is obscure. The most cogent theory is that it represents a hypersensitivity reaction, possibly autoimmune in nature, to an as yet unknown antigen.