Incidentally detected increased FDG uptake in bowel and its correlation with hystopathological data: our experience in a case series study.

Abstract

When an intense intestinal FDG accumulation occurs, especially if focal, it can be referred to either physiological intestinal activity or bowel disease, thus leading to a radical change in patient's prognosis. Within a year, we recommended a colonoscopy to 103 of 7365 patients who were subjected to a total body FDG PET/CT. In a case-series study, we re-evaluated the patients and their lesions if already investigated with colonoscopy and biopsy. Only 18 patients were included in our study, but in none of them biopsy was negative and 3 adenocarcinomas, 8 adenomas, 5 inflammatory patterns, 1 hyperplastic polyp and 1 eosinophilic infiltrate were diagnosed. In 16 patients, no suspicion was present and diagnosis was absolutely incidental. Besides, among the three major groups (adenocarcinomas, adenomas and phlogosis), SUVmax values were significantly different. Adenocarcinomas are linked with high SUVmax values (ranging from 8.3 to 20.2) and large size (ranging from 26 to 43 mm). PET/CT sensitivity is low in detecting adenomas, being 71.4% if they are larger than 6 mm and 50% if SUVmax is lower than 4.9. SUVmax values in inflammatory lesions can range from 5.7 to 12. Colorectal cancer is still the second leading cause of cancer death, for this reason in many countries screening programs have been approved and colonoscopy is considered the golden standard. PET/CT cannot be considered as a screening test, but if it incidentally reveals intestinal abnormalities, this data cannot be underestimated and colonoscopy is highly recommended.