RESUMO
Odontogenic myxofibroma of the temporomandibular joint (TMJ) is a rare tumour; moreover, primary splenic angiosarcoma (PAS) in paediatric patients is extremely rare. We report on a 15-year-old boy who presented with right TMJ swelling and subsequently developed epigastric and right upper quadrant pain. The TMJ swelling proved to be odontogenic myxofibroma and the abdominal pain was a result of primary splenic angiosarcoma with hepatic metastasis. We report for the first time the synchronous presentation of PAS and odontogenic myxofibroma in a paediatric patient, and we describe the radiological features along with the histological diagnosis and clinical outcome. Uptake in (18)F-2-fluoro-2-deoxy-D-glucose positron emission tomography is also described for the first time for both these tumours.