Final answer:
Retroperitoneal fibrosis is a rare condition characterized by the abnormal growth of fibrous tissue in the retroperitoneum. It can cause compression and obstruction of nearby structures, leading to symptoms such as flank pain, urinary obstruction, and hypertension.
Step-by-step explanation:
The fibrous tissue proliferation affecting and encasing the aorta, ureters, in the retroperitoneum is known as retroperitoneal fibrosis. Retroperitoneal fibrosis is a rare condition characterized by the abnormal growth of fibrous tissue in the retroperitoneum, the area behind the abdominal cavity. It can cause compression and obstruction of nearby structures, leading to symptoms such as flank pain, urinary obstruction, and hypertension.