FDG PET/CT is considered an accurate method for the detection of recurrent rectal cancer in the pelvis. Excess presacral soft tissue is found in up to half of patients after (chemo)radiation and surgery for rectal cancer, and usually represents fibrosis that is metabolically inactive. However, presacral soft tissue that is FDG avid is generally considered suspicious for recurrent cancer. Nevertheless, FDG avidity in the presacral space not uncommonly proves to be due to benign inflammatory changes, and additional MRI may be diagnostically useful, as demonstrated in the presented 2 cases.
From the Department of *Radiology, Nuclear Medicine, and Molecular Imaging, Medical Imaging Center; and
†Department of Surgery, Section of Hepato-Pancreato-Biliary Surgery and Liver Transplantation, University Medical Center Groningen, University of Groningen, Groningen, the Netherlands.
Received for publication April 6, 2018; revision accepted February 5, 2019.
Conflicts of interest and sources of funding: none declared.
Correspondence to: Jan P. Pennings, MD, Department of Radiology, Nuclear Medicine, and Molecular Imaging, Medical Imaging Center, University Medical Center Groningen, University of Groningen, Hanzeplein 1, PO Box 30.001, 9700 RB Groningen, the Netherlands. E-mail: firstname.lastname@example.org.