Idiopathic presacral retroperitoneal fibrosis: report of two cases

Imaging of presacral masses--a multidisciplinary approach

Our objective is to describe an approach for retrorectal/presacral mass evaluation on imaging with attention to imaging features, allowing for refinement of the differential diagnosis of these masses. Elaborate on clinically relevant features that may affect biopsy or surgical approach, of which the radiologist should be aware. A review of current literature regarding the diagnosis and treatment of retrorectal/presacral masses was performed with attention to specific findings, which may lend refinement to the differential diagnosis of these masses. Cases were obtained by searching through a radiology database at a single institution after Institutional Review Board approval. Recent advances in imaging and treatment methods have led to the increased role of radiology in both imaging and tissue diagnosis of retrorectal masses. Surgical philosophies surrounding the treatment of these masses have not significantly changed in recent years, but there are a few key factors of which the radiologist must be aware. The radiologist can offer refinement of the differential diagnosis of retrorectal masses and can elaborate on salient findings which could alter the need for neoadjuvant chemoradiation therapy, pre-surgical tissue diagnosis and surgical approach. This article presents an imaging approach to retrorectal/presacral masses with emphasis on findings which can dictate the ultimate need for neoadjuvant therapy and pre-surgical tissue diagnosis and alter the preferred surgical approach. This article consolidates key findings, so radiologists can become more clinically relevant in the evaluation of these masses.

[Case of pelvic retroperitoneal fibrosis]

A 66-year-old man visited his nearby clinic with a complaint of left lower abdominal pain. Abdominal CT scan showed left hydronephrosis due to lower ureteral involvement by infiltrative retroperitoneal mass located outside of the left posterior wall of the bladder and left seminal vesicle. He was referred to our hospital for further examination. Pathological diagnosis of the percutaneous CT-guided biopsy of retroperitoneal mass was fibrosis without any malignant tumor. Because we could not rule out the possibility of the secondary fibrosis accompanied by malignant tumor, we performed surgical resection of the retroperitoneal mass involving left ureter and confirmed that the mass contains no malignant tumor by frozen section analysis. We augmented the defected ureter by Boari flap method. We should be noticed that retroperitoneal fibrosis could be a differential diagnosis of retroperitoneal pelvic mass.

Fibrosing mediastinitis manifesting as thoracic prevertebral thin band-like mass on MRI and PET-CT

To our knowledge, no report exists of a posterior mediastinal thin band-like mass as a manifestation of fibrosing mediastinitis. A man showed right pleural effusion on chest radiograph. On CT, there was a band-like mass on thoracic prevertebral area. MRI demonstrated the enhancing longitudinal band-like mass all along the vertebrae on coronal and sagittal scans. It was hypermetabolic on PET-CT and there was another hot mass in the presacral area. Additional pelvic MRI showed presacral mass with aortic encasement. Biopsy specimen was consistent with fibrosing mediastinitis. We report a case of fibrosing mediastinitis of posterior mediastinum manifesting as thoracic prevertebral band-like mass and discontiguous presacral, periaortic mass studied with CT, MRI and PET-CT.