Concurrent FDG-Avid and Non-FDG-Avid Pleomorphic Adenomas in the Submandibular Gland and Parapharyngeal Space.

Pleomorphic adenoma is the most common benign tumor of salivary glands. Here we present an interesting case of concurrent pleomorphic adenomas in the parapharyngeal space and submandibular gland. The tumors showed stark differences in the imaging findings on FDG PET/CT and MRI. Pathology confirmed the diagnosis of pleomorphic adenomas with the different composition of the cellular component and chondromyxoid stroma. This case suggests that the difference in cellularity of pleomorphic adenomas can affect FDG uptake and diffusion-weighted MRI-derived apparent diffusion coefficient values.