Variety and complexity of fluorine-18-labelled fluoro-2-deoxy-d-glucose accumulations in the oral cavity of patients with oral cancers

Objectives:To elucidate the points that require attention when interpreting fluorine-18-labelled fluoro-2-deoxy-d-glucose (18F-FDG)/positron emission tomography (PET) images by demonstration of 18F-FDG accumulation in various areas of the oral cavity other than primary lesions in patients with oral cancers.Methods:18F-FDG accumulations with a maximal standardized uptake value of over 2.5 in various areas of the oral cavity other than primary lesions were identified in 82 patients with oral cancers.Results:18F-FDG/PET-positive areas, excluding primary tumours, included the front intrinsic muscles of the tongue (89.0%), upper and lower marginal parts of the orbicularis oris muscle (64.6%), sublingual glands, palatine tonsil, pharyngeal tonsil, and lingual tonsil. In addition, some areas in the jaws also showed accumulation.Conclusions:In patients with oral cancers, areas of 18F-FDG accumulation in the oral cavity should be precisely identified and appropriately diagnosed, because accumulations can be seen i...