TITLE: Solitary Fibrous Tumour arising in the Parapharyngeal Space Authors’ names and affilations

Solitary fibrous tumour (SFT) is a mesenchymal tumour, which is most often encounterd in the pleura. Although the tumour was initially regarded as being derived only from submesothelial fibroblasts and therefore restricted to mesothelial-lined surfaces, recent reports have documented the existence of these lesions at sites unrelated to the serosal surface, including the head and neck. Here, we report a rare case of SFT arising in the parapharyngeal space, which showed interesting features on MRI, CT, and F-fluorodeoxyglucose (FDG) positron emission tomography (PET) findings. A 38-year-old man presented with a persistent bulging mass at the left oropharyngeal wall. On the CT images, the mass was located in the anterior compartment of the left parapharyngeal space, which showed the heterogenous enhancement on contrast-enhanced CT findings. On MRI, the tumour showed nodule-in-nodule appearance. The inner nodule showed high signal intensities both on T1and T2-weighted MR images. The entire tumour showed hetrogenous enhancement on Gadlinium-enhanced T1-weighted images except for a part of inner nodule. FDG-PET showed the heterogenous radiotracer uptake of FDG in the inner nodule of