Incidentally-Detected Colorectal Neoplasms on PET-CT Scans*
Background:
The detection and clinical reporting of unexpected focal uptake of FDG within the bowel on PET scans is increasing in prevalence with the increasing utilisation of this imaging modality. These scan findings may subsequently reveal malignant or pre-malignant pathology. In addition to reporting the incidence of malignant and pre-malignant diagnoses detected in this manner, this study analysed the correlation between pathological colonic segments to those reported on the original scan as showing abnormal foci of FDG uptake.
Methods:
The reports of 1985 PET-CT scans were reviewed for documentation of unexpected foci of FDG uptake in the bowel. Information regarding demographics and the subsequent management was collected from the patients’ medical records. The segments harbouring foci of unexpected bowel FDG uptake were noted and compared against the eventual outcome(s) of the endoscopic and pathological investigations.
Results:
Among the 62 individual patients represented, 10 were diagnosed with a previously unsuspected colorectal carcinoma. Additionally, an unknown bowel lymphoma and 19 colonic adenomas were discovered. The segments in which the pathological findings were identified generally correlated well with those reported at PET-CT as bearing unexplained focal uptake.
Conclusion:
The findings confirm the recommendations of comparable studies that investigation of unexpected foci of bowel FDG uptake on PET-CT should be undertaken where practical and clinically warranted. The correlation between colonic segments identified as pathological on endoscopic investigation with those reported on PET-CT was strong. In particular, focal FDG uptake in the proximal colon is associated with a high sensitivity for malignancy.