Geniculate ganglion mass

Findings:

Right petrous temporal bone:

The right geniculate ganglion is mildly expanded compared to the left, and measures 3.5 mm. No internal bony spiculations identified within the expanded geniculate ganglion. The fallopian canal, tympanic portion, posterior genu and mastoid portion of the facial nerve have an unremarkable appearance. 

The right jugular bulb is high riding. The right sigmoid plate is extremely thin. The ossicles and scutum have a normal appearance. The tegmen tympani is intact. The middle ear, aditus ad antrum, mastoid antrum and mastoid air cells are clear. The vestibular aqueduct is not enlarged. The inner ear structures have a normal appearance. The internal auditory canal is not expanded compared to contralateral side. The external auditory canal is clear.

Left petrous temporal bone:

The left jugular bulb is high riding, with thin sigmoid plate. The intraosseous left facial nerve has an unremarkable appearance.

Conclusion:

1. Asymmetric enlargement of the right geniculate ganglion in this clinical setting raises the possibility of a geniculate ganglion mass. Possibilities include a facial nerve schwannoma or hemangioma. Further characterization with MRI is recommended.

2. Bilateral high riding jugular bulbs.

MRI brain (acoustic neuroma (IAM) protocol)

Technique:

Multiplanar, multisequence imaging has been obtained through the brain including high resolution 3D iso T2 CISS sequence through the posterior fossa, and post-contrast fat saturated sequences.

Findings:

There is a 3.5 millimeter soft tissue mass centered upon the right geniculate ganglion that shows vivid contrast enhancement. The contrast enhancement appears almost entirely confined to the ganglion, but may extend into the origin of the greater superficial petrosal nerve.

Conclusion:

Right geniculate ganglion mass, without internal osseous spiculations on CT. The most likely diagnosis is schwannoma of the right geniculate ganglion, with a differential of facial nerve hemangioma.