Original articlePitfalls and mimickers on 18F-FDG-PET/CT in peritoneal carcinomatosis from colorectal cancer: An analysis from 37 patients

SummaryBackgroundOptimal selection is critical in patients with peritoneal carcinomatosis (PC) in whom curative cytoreductive surgery can be anticipated. 18F-FDG-PET/CT may result in false-positive findings that may eliminate patients for whom cytoreductive surgery would be beneficial.ObjectivesTo determine the rate of false-positive findings on 18F-FDG-PET/CT and clarify their causes in patients with suspected PC from colorectal cancer.MethodsA retrospective analysis of 37 patients with suspected PC from colorectal cancer who had 18F-FDG-PET/CT before cytoreductive surgery was performed to determine the rate and the causes of false-positive findings. 18F-FDG-PET/CT was considered falsely positive when no tumor was found at surgery, histopathological analysis and follow-up.ResultsFalse-positive findings were observed in four patients, yielding a 11% (95%CI: 3-25%) false-positive rate on a per-patient basis. The causes of false-positives were elucidated in two patients (surgical mesh after umbilical hernia repair and one foreign body granuloma).ConclusionFalse-positive findings on 18F-FDG-PET/CT are observed in 11% of patients with suspected PC from colorectal cancer. Familiarity with false-positive findings would result in more accurate selection of patients candidates to cytoreductive surgery.