[Riedel's thyroiditis and retroperitoneal fibrosis. Apropos of a case of multiple fibrosing disease].

The authors report a case of a 53 year old woman with Riedel's thyroiditis and retroperitoneal fibrosis. The thyroiditis has been diagnosed a year before the retroperitoneal fibrosis. This one was idiopathic and has been responsible of the death of the patient during an operation performed for ureterolysis. Fifteen other similar cases have been reported in the literature: four of them associated also mediastinal and biliary ducts fibrosis. The existence in one patient of multiple fibrosclerosis locations and the similitude of histological patterns (inflammatory diffuse fibrosis) lead to the concept of a multiple sclerosing disorder involving Riedel's thyroiditis, Ormond's disease, mediastinal fibrosis, sclerosing cholangitis, and the pseudotumors of the orbit. The etiopathogenic processes remain unclear.