Detection of a primary tumor in the area of the renal artery with 18F-FDG PET/CT in a patient with metastatic undifferentiated sarcoma and a history of mid-aortic syndrome: A case report.

Background: We present a case of a 57-year-old woman patient with a history of mid-aortic syndrome, treated with several vascular procedures, who was referred for investigation of metastatic disease of an undifferentiated sarcoma of unknown origin.

Methods: Positron emission tomography/computed tomography (PET/CT) demonstrated multiple fluorodeoxyglucose (F-FDG) avid lung, liver, and osseous metastases as well as a focus of increased F-FDG uptake in the area of the stented left renal artery.

Result: Histologic evaluation of soft tissue from the region of the left renal artery revealed atypical spindle cells, consistent with an intimal sarcoma, and with histopathological characteristics identical to those of lung metastases, indicating the F-FDG avid lesion in the area of the renal artery as the origin of the metastatic disease.

Conclusion: This case highlights the capacity of F-FDG PET/CT to detect primary tumors even of small size and in unusual localisations. Moreover, it provides further indications regarding the potential association between foreign body reaction on the basis of chronic inflammation and sarcoma development.