Primary parapharyngeal and skull base synovial sarcoma in a 13-year-old boy with neurofibromatosis radiologically misdiagnosed as a benign lesion.

Synovial sarcoma is a rare form of malignant tumour and accounting approximately for 8% of all soft tissue sarcomas. Head and neck synovial sarcomas are uncommon and parapharyngeal space involvement is extremely rare. We report a case of synovial sarcoma in the parapharyngeal space of a 13-year-old boy with a history of neurofibromatosis presented with odynophagia, ptosis and left submandibular mass. The lesion extended from retrostyloid parapharyngeal space to the skull base and foramen jugular superiorly. The first clinical and radiological impressions were carotid jugular related tumours such as schwannoma and paraganglioma.