Idiopathic Retroperitoneal Fibrosis Presenting as a Podagra-Like Condition: A Case Report

Retroperitoneal fibrosis (RPF) is a rare fibroinflammatory disorder in which fibrous tissue forms around the infrarenal aorta and iliac vessels, often compressing the ureters and causing obstructive uropathy and renal impairment.It typically presents insidiously with back, flank, or abdominal pain and constitutional symptoms.We describe a 52-year-old man with a background of hypertension who presented on three occasions over 10 months with an acutely painful, swollen first metatarsophalangeal (MTP) joint, initially on the left and subsequently on the right.The first two episodes were managed as presumed gout, with naproxen and then a short course of oral prednisolone, and his symptoms settled between attendances.His serum urate and creatinine rose across these attendances.At his third presentation, he was incidentally found to be hypertensive with severe renal impairment and was admitted.Imaging demonstrated bilateral hydronephrosis secondary to ureteric compression by a confluent para-aortic soft tissue mass.Following further investigation and specialist multidisciplinary team review, a working diagnosis of idiopathic RPF was made.Bilateral nephrostomies relieved the obstruction, and he was commenced on prednisolone and mycophenolate mofetil.He remains under urology and rheumatology follow-up, with serial renal function monitoring and radiological surveillance of the mass, nine months after diagnosis.This case illustrates a podagra-like presentation of idiopathic RPF and highlights the value of maintaining a broad differential diagnosis in recurrent monoarthritis with declining renal function and the importance of excluding malignancy before an idiopathic label is applied, particularly when tissue diagnosis is not feasible.