A Pitfall of Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Fecal Peritonitis Mimicking Peritoneal Carcinomatosis

Authors

  • Julie Kjems Department of Nuclear Medicine, Herlev University Hospital, The Capital Region
  • Lisbeth Marner Department of Nuclear Medicine, Herlev University Hospital, The Capital Region/Department of Clinical Medicine, University of Copenhagen
  • Jakob Hagen Vasehus Schou Department of Oncology, Herlev University Hospital, The Capital Region
  • Carina Kirstine Klarskov Department of Nuclear Medicine, Herlev University Hospital, The Capital Region

DOI:

https://doi.org/10.3941/jrcr.6001

Abstract

Background: Postoperative inflammatory reactions, such as foreign-body responses, can mimic peritoneal carcinomatosis on fluorodeoxyglucose positron emission tomography, potentially leading to misdiagnosis.
Case presentation: A 65-year-old woman with colon adenocarcinoma developed fecal peritonitis after surgery. Rising carcinoembryonic antigen and imaging findings suggested peritoneal carcinomatosis. Repeated biopsies revealed inflammatory tissue with foreign material consistent with prior peritonitis. Follow-up imaging and biomarker normalization confirmed a benign etiology despite persistent uptake.
Conclusion: Interpretation of postoperative fluorodeoxyglucose positron emission tomography requires integration of imaging, histology, and clinical context to avoid unnecessary treatment.

Laboratory values for C-reactive protein (CRP) and carcinoembryonic antigen (CEA) for a 65-year-old woman with adenocarcinoma of the colon, initially staged T4aN1bM0. FDG PET/CT findings are in the top (orange boxes) and surgical information in the bottom (green boxes). The dashed blue line is depicting the CEA cut off value of 5 ?g/L. CRP values are depicted as the maximum CRP value per month.

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Published

2026-02-28

Issue

Vol. 20 No. 2 (2026)

Section

Nuclear Medicine / Molecular Imaging

License

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