Positron emission tomographic imaging of pleomorphic adenoma in the parotid gland

We studied the possible correlation between 2-18F-2-deoxy-D-glucose (FDG) uptake and histopathological findings in mass lesions of the parotid gland. Thirteen pleomorphic adenomas of the parotid gland were evaluated by computed tomography (CT), magnetic resonance imaging (MRI), Gallium scintigraphy, Technetium scintigraphy and FDG-positron emission tomography (PET). Standardized uptake values (SUV) and time-activity curves (TAC) were determined for all mass lesions. Pleomorphic adenomas were histologically classified into the following three types: epithelial, intermediate and mesenchymal, based on their dominant histological components. The numbers of epithelial, intermediate, and mesenchymal types were 5, 2, and 6, respectively. The levels of SUVs were 4.02 +/- 1.91 (range: 1.97-7.07) in the epithelial type, 5.05 +/- 1.12 (range: 4.26-5.58) in the intermediate type and 3.98 +/- 7.74 (range: 1.98-7.74) in the mesenchymal type, respectively. The accumulation of FDG did not differ significantly among the three types. Since the accumulation of FDG was significantly correlated with the tumor size, FDG-PET could reflect tumor growth ability more apparently than the other nuclear or imaging modalities.