Jugulotympanic paraganglioma

Left glomus jugulare paragangliomajugulotympanicum paraganglioma with typical MRI and CT imaging characteristics.  This was discovered incidentally in the setting of traumatic brain injury. This patient has a past history of previous right caroticocavernous fistula transvenous coil embolisation.  

Mass lesion centred within the left jugular foramen with tympanic extension to the cochlear promontory and which descends into the carotid space just below the skull base. It enhances vividly and demonstrates mixed T2 and T1 signal including many small low signal flow voids creating a salt and pepper appearance. The mass causes complete effacement of the left internal jugular vein and displaces the left internal carotid artery anteriorly. Altered flow signal within the left transverse and sigmoid sinuses on the T1 images is likely due to slow flow, with no thrombosis seen on the post-contrast images.

Bilateral paramedian inferior frontal lobe gliosis (best seen on coronal T2 images) is in keeping with prior traumatic brain injury. Abnormal low T2 signal within the posterior aspect of the right cavernous sinus relates to coils from prior transvenous treatment of carotid-cavernous fistula. 

Irregular bone erosion (moth-eaten appearance) is seen at the margins of the left jugular foramen with the soft-tissue mass extending into the middle ear cavity at the cochlear promontory. This is aThe bone erosion and growth pattern are typical featurefeatures of glomus jugularejugulotympanicum paragangliomas and are useful to help distinguish between schwannoma which will cause smooth remodeling of the foramen.  

T2 fat saturated and T1 images demonstrating low signal flow voids within a carotid space mass (red arrows) which descends for the jugular foramen. This is the classic "salt and pepper" appearance of paraganglioma.

Axial bone CT shows irregular erosion of bone at the margin of the jugular foramen (yellow arrows) which is a useful feature to help differentiate glomus jugulare paragangliomas from schwannomas which tend to cause smooth remodeling of the foramen.