FIG 3. Initial axial view contrast-enhanced CT scan of a 61-year-old woman who noted a slowly growing mass of the left external fossa that was associated with intermittent pain in the left temporomandibular joint. A tumor of the left infratemporal fossa, with intra-tumoral calcifications (arrowheads), can be seen. The lesion is invading the left temporal muscle and the left greater wing of the sphenoid bone (arrow). Histologically, it is a spindle cell monophasic synovial sarcoma. No recurrence had occurred 8 years after surgery and radiotherapy.

FIG 4. Images from the case of an 18-year-old female patient who presented with a synovial sarcoma arising from the right infratemporal fossa.

A, Axial view T1-weighted MR image (600/20/2 [TR/TE/ excitations]) shows a voluminous, homogeneous mass involving the right lateral pterygoid and temporal muscles and displacing the posterior wall of the right maxillary sinus anteriorly. The lesion exhibits an isointense signal (arrow).

B, Axial view T2-weighted MR image (2000/100/1) shows a voluminous, homogeneous mass involving the right lateral pterygoid and temporal muscles and displacing the posterior wall of the right maxillary sinus anteriorly. The lesion exhibits a hypointense signal (arrow)