A case of chronic periaortitis with retroperitoneal fibrosis

Non-infectious diseases of the aorta and large arteries

This article describes the various forms of inflammatory lesions of the aorta and large arteries, including chronic periaortitis, as well as the diagnostic methods are considered. Large vessel vasculitis represent the most common entities, however, there is also an association with other rheumatological or inflammatory diseases, drug-induced or paraneoplastic entities. Instrumental imaging modalities play an important role in the diagnosis.

The value of 18F-FDG PET/CT in the distinction between retroperitoneal fibrosis and its malignant mimics

OBJECTIVE

To discuss the utility of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computerized tomography (PET/CT) in the diagnosis of idiopathic retroperitoneal fibrosis (iRPF).

METHODS

IRPF patients diagnosed between September 2011 and June 2016 were included. Retroperitoneal malignancy patients were included as control. The morphological features and FDG uptake of retroperitoneal lesions were measured along with lymph node (LN) mapping.

RESULTS

Seventy-one iRPF patients were included. Fifteen lymphoma patients and 6 retroperitoneal metastatic malignancy patients were included as control. Significant differences in morphological features were observed between iRPF and lymphoma but not retroperitoneal metastatic carcinoma. Compared with malignancy, iRPF displayed a lower frequency of high-FDG-uptake retroperitoneal lesions (P = 0.017) and a lower mean maximum standardized uptake value (SUV_max) (P < 0.001). LNs located at axillary, retroperitoneal, supraclavicular, inguinal or peritoneal sites were more frequently observed in retroperitoneal malignancy, therefore, were defined as specific LNs. The area under the curve (AUC) for SUV_max was 0.893 with a sensitivity of 85.7% and a specificity of 80.3%, when the cut-off value of the SUV_max was 6.23. The AUC for the logistic regression model combining the lesions above renal arteries, the SUV_max and the number of specific LNs was 0.987 with a sensitivity of 90.5% and a specificity of 98.6%. The risk stratification model analysis indicated that most of the retroperitoneal malignancy patients were at moderate or high level, while most of the iRPF patients were at low risk.

CONCLUSIONS

Retroperitoneal malignancy can mimic iRPF morphologically. ¹⁸F-FDG PET/CT can help to distinguish iRPF from retroperitoneal lymphoma and metastatic malignancy.