Glomus Jugulotympanicum Paraganglioma

glomus jugulotympanicum

This patient presented for further assessment of a known paraganglioma. The axial post-gadolinium T1-weighted image above (click image for arrows) shows an enhancing lesion involving almost the entire petrous temporal bone and extending through the external auditory canal to protrude from the external ear (green arrow). The tumour extended beyond the skull base into the carotid sheath, and bulged into the posterior fossa.

Paragangiomas of the jugulotympanic region may be confined to the middle ear (glomus tympanicum), confined to the jugular foramen (glomus jugulare), or involve both spaces with associated bone erosion (glomus jugulotympanicum). The latter may grow large and extend into the external ear, as in this case. Presentation is with pulsatile tinnitus, cranial nerve palsies (typically IX-XI, Vernet syndrome), or conductive deafness. Examination may reveal a vascular retrotympanic mass. When bone erosion occurs it is best seen with CT, and a moth-eaten pattern is typical. MRI may show a “salt and pepper” appearance on T1 weighted images – salt being blood products from haemorrhage (uncommon) and pepper being flow voids due to high vascularity (common). Angiography should demonstrate an intense tumour blush, with the most common feeding vessel being the ascending pharyngeal. Treament is usually by excision – preoperative endovascular embolisation is often used to reduce tumour vascularity and aid excision. Radiotherapy is used for palliation of unresectable lesions.

Reference: Rao AB, Koeller KK, Adair CF. Paragangliomas of the Head and Neck: Radiologic-Pathologic Correlation. Radiographics 1999; 19:1605-1632.

Credit: Dr Laughlin Dawes