Hashimoto's thyroiditis associated with idiopathic retroperitoneal fibrosis: case report and review of the literature.

Idiopathic retroperitoneal fibrosis (IRF) is a rare disease of unknown origin, characterised by an inflammatory proliferative fibrosing process occurring in the retroperitoneum. Hashimoto's thyroiditis (HT) is a form of chronic thyroiditis that in some cases shows an extensive replacement of thyroid parenchyma by fibrous tissue. We report the rare association of IRF with HT in a 68-year-old woman presenting with pulmonary oedema, acute renal failure due to bilateral hydronephrosis and a firm diffuse goitre with hypothyroidism. The so far reported cases of IRF associated with chronic thyroiditis are reviewed, and the possible aetiopathogenetic link between these two entities is discussed.