Retroperitoneal Fibrosis Secondary to Tuberculosis and Sigmoid Colon Cancer: Two Case Reports Presenting with Acute Obstructive Renal Failure and a Review of the Literature

Retroperitoneal fibrosis is a rare condition, with an estimated incidence between 1 in 200,000 and 1 in 500,000 per year, characterized by the proliferation of fibrous tissue in the retroperitoneal space, which can compress the ureters and cause acute obstructive renal failure. It may be idiopathic or secondary to various causes, including infections such as tuberculosis or malignancies such as sigmoid colon cancer. We report two distinct cases: a 42-year-old woman with tuberculous retroperitoneal fibrosis presenting with low back pain and anuria, successfully treated with corticosteroids and antituberculosis therapy; and a 25-year-old man with post-surgical retroperitoneal fibrosis secondary to sigmoid adenocarcinoma, who progressed to chronic renal failure despite oncologic management. A review of the literature indicates that these secondary forms, although rare, involve inflammatory (tuberculosis) or desmoplastic (cancer) mechanisms. Diagnosis is based on imaging (ultrasound, CT scan, magnetic resonance imaging), and treatment is guided by the underlying etiology. These cases highlight the importance of a multidisciplinary approach to determine the cause and optimize outcomes.