Retroperitoneal fibrosis (chronic periaortitis)

In Retroperitoneal fibrosis condition the ureters become embedded in dense retroperitoneal fibrous tissue with resultant unilateral or bilateral obstruction. The condition may extend from the level of the second lumbar vertebra to the pelvic brim. The incidence of the condition in men is three times that in women.

An autoallergic response to leakage of material, probably ceroid, derived from atheromatous plaques is considered to be the underlying cause of the condition. Recognized associations are with abdominal aortic aneurysm and prolonged exposure to the drug methysergide. The differential diagnosis includes retroperitoneal lymphoma or cancer.

Malaise, back pain, normochromic anaemia, uraemia and a raised erythrocyte sedimentation rate (ESR) are typical features. Excretion urography shows bilateral or unilateral ureteric obstruction commencing at the level of the pelvic brim. A periaortic mass may be seen on a CT scan.

Obstruction is relieved surgically by ureterolysis. Biopsy should be performed at operation to determine whether there is an underlying lymphoma or carcinoma. Corticosteroids are of benefit, and in bilateral obstruction in frail patients it may be best to free only one ureter and to rely upon steroid therapy to induce regression of fibrous tissue on the contralateral side, since bilateral ureterolysis is a major operation. In some patients, surgery alone or steroid therapy alone may suffice, but in the majority both surgery and subsequent corticosteroid therapy appear to be necessary.

An alternative approach is to relieve obstruction by placement of a ureteric stent or stents, and to rely on corticosteroid therapy to induce regression of the periaortic mass, with later stent removal. A disadvantage is that an adequate biopsy of the mass - readily obtainable on open operation - is not easily obtained and regular (usually 6-monthly) changes of the stent or stents is required if the periaortic mass does not regress.

Treatment of Retroperitoneal fibrosis

Response to treatment and disease activity are assessed by serial measurements of ESR and GFR supplemented by isotopic and imaging techniques including CT scanning. The latter method enables the size of the retroperitoneal mass to be assessed.

Relapse after withdrawal of steroid therapy may occur and treatment may need to be continued for years. Long-term follow-up is mandatory.