A 65-year-old woman was addressed for clinical and biological suspicion of ovarian cancer relapse. 18F-FDG PET/CT revealed massive peritoneal carcinomatosis. Post-chemotherapy PET/CT showed complete metabolic response in initial localizations albeit three new 18F-FDG uptakes appeared in the mesentery and in the retro-hepatic space. Close follow-up (including PET/ CT scan) and surgical examination of the abdominal cavity confirmed the absence of malignancy and the benign nature of these lesions, which appeared to be peritoneal fibrosis mimicking persistent carcinomatosis.