Synchronous primary neoplasms detected on 18F-FDG PET in staging of patients with esophageal cancer

Because of improvements in diagnostic technology, the incidental detection of synchronous primary tumors during the preoperative work-up of patients with esophageal cancer has increased. The aim of this study was to determine the rate and clinical relevance of synchronous neoplasms seen on F-18-FDG PET in staging of esophageal cancer. Methods: From January 1996 to July 2004, 366 patients with biopsy-proven malignancy of the esophagus underwent F-18-FDG PET for initial staging. This series of patients was retrospectively reviewed for the detection of synchronous primary neoplasms. Results: Twenty synchronous primary neoplasms (5.5%) were identified in 366 patients. Eleven neoplasms were in the colorectum, 5 in the kidney, 2 in the thyroid gland, 1 in the lung, and 1 in the gingiva. One of the thyroid lesions and the lung lesion were erroneously interpreted as metastases, leading to incorrect upstaging of the esophageal tumor. Conclusion: F-18-FDG PET detected unexpected synchronous primary neoplasms in 5.5% of patients with esophageal cancer. Sites of pathologic F-18-FDG uptake should be confirmed by dedicated additional investigations before treatment, because synchronous neoplasms may mimic metastases.