Enlarged cervical sympathetic ganglion: an unusual parapharyngeal space tumour.

Primary parapharyngeal space tumours are rare, but they pose not only diagnostic but also therapeutic challenges in head and neck surgery. Imaging studies, in particular magnetic resonance (MR) imaging, play a central role in the diagnosis of parapharyngeal space (PPS) tumours. Besides schwannomas, primary lesions arising from the sympathetic chain within the PPS are extremely rare. We describe a 49-year-old man in whom the cervical sympathetic ganglion became enlarged after radiotherapy for nasopharyngeal carcinoma, and appeared as a parapharyngeal mass. This phenomenon has not been reported in the literature. We also discuss the features of the enlarged cervical sympathetic ganglion on MR imaging.