Retroperitoneal Manifestations Retroperitoneal involvement in ECD is secondary to infiltration of the fat and surrounding structures by histiocytes and associated fibrosis. CT findings range from fat stranding in the retroperitoneum to soft tissue masses in the retroperitoneum. This may result in hydronephrosis leading to renal failure and hypertension. Periaortic fibrosis has been described and has been shown to involve the entire aorta and its branches causing lower extremity claudications. The most common pulmonary symptom is progressive dyspnea.
Chest radiographs demonstrate diffuse interstitial prominence and pleural thickening.
CT typically shows interlobular septal and pleural thickening. Other findings include patchy centrilobular ground glass opacities. The prognosis for ECD is related to the extent of visceral involvement. Most patients die within two to three years after diagnosis due to congestive heart failure, lung fibrosis or renal insufficiency. Treatment options include corticosteriods, radiotherapy, chemotherapy and immunotherapy or combination therapy.