F-18-fluorodeoxyglucose positron emission tomography (18-FDG PET/CT) is increasingly being used in patients with cancer, both for baseline staging and for evaluation of treatment response. However, in patients with incidental irradiation of the liver during radiotherapy, particularly for lower gastrointestinal tract cancers, increased focal F-18-fluorodeoxyglucose positron emission tomography avidity may be the result of collateral radiation induced liver damage rather than metastases. Awareness of this pathologic entity and correlation with with other imaging, clinical and laboratory findings including liver biopsy is vital to avoid misinterpretation and overstaging of the carcinoma in these patients. We encountered such a scenario in an elderly female patient with distal esophageal squamous cell carcinoma patient, who developed F-18-fluorodeoxyglucose positron emission tomography avid left lobe liver lesion post neoadjuvant radiotherapy, simulating interval metastasis. A liver biopsy ruled out malignancy and helped to clinch the correct diagnosis of radiation induced liver injury.
Keywords: esophageal cancer; interval metastasis; radiation induced damage; radiotherapy; treatment.