Chronic periaortitis (CP) is a rare condition, hallmarked by periaortic fibro-inflammatory tissue which often causes ureteral obstruction, and encompasses idiopathic retroperitoneal fibrosis and inflammatory abdominal aortic aneurysm (IAAA). CP usually responds to glucocorticoids, but some patients may be steroid-refractory or not tolerate standard glucocorticoid doses. For such cases, valid therapeutic alternatives are lacking.1 2 Combinations of prednisone and immunosuppressants (eg, cyclophosphamide, mycophenolate mofetil) are not of proven superiority to prednisone alone, and their effectiveness in refractory CP is unknown.3 4 Because B cells abundantly infiltrate CP lesions,5 and CP is often associated with autoimmune diseases,6 we used rituximab in two patients with CP, one refractory to conventional treatments, and the other with contraindications to standard-dose glucocorticoids.

Our first patient, a 49-year-old woman, was hospitalised for malaise and back pain. Abdominal CT revealed a soft-tissue-density periaortic mass suggesting CP, a diagnosis confirmed by laparoscopic biopsy (figure 1). The patient responded to prednisone (initial dose, 1 mg/kg/day), with symptom remission and reduction in CP thickness, but relapsed with back pain and CP enlargement when the prednisone dose was 5 mg/day (8 months after treatment initiation). …