Retroperitoneal Fibrosis in a Patient with Rheumatoid Arthritis

ABSTRACT

A 54-year-old male diagnosed with rheumatoid arthritis (RA) was effectively treated with methotrexate and adalimumab. He was admitted with fatigue and right lower back pain which had persisted for 1 month. An enhanced abdominal computed tomography scan showed an ill-defined mass with soft tissue attenuation surrounding the right common iliac artery involving the right middle portion of the ureter. Laparoscopic ureterolysis and biopsy were performed. Microscopic evaluation confirmed the presence of fibroblastic proliferation, with a pleomorphic inflammatory cell infiltrate consisting predominantly of lymphocytes, macrophages, and vascular endothelial cells, without granuloma or neoplastic cells. Therefore, our diagnosis was retroperitoneal fibrosis (RPF)-associated RA. Clinicians should consider the possibility of RPF in patients with RA who experience lower back pain, abdominal pain, or dysuria, and order suitable imaging studies.