Presentation
75 year old male with vertebrobasilar dolichoectasia and history of remote left cranial nerve VII surgery (1992) for unknown reason, now presenting with left hemifacial spasm, intractable vertigo, and tinnitus.
Patient Data
ASNR 2016: This case was submitted as part of the American Society of Neuroradiology (ASNR 2016) Case Of The Day competition, in collaboration with Radiopaedia.org.
There is focal curvilinear calcification along the ventral surface of the left cerebellum in the region of the cerebellopontine angle cistern.
There is a well-circumscribed lesion of intermediate to low signal intensity on the T2 FIESTA sequence abutting the left VII/VIII nerve root entry zone and inseparable from the dorsal aspects of the left vertebral and posterior inferior cerebellar arteries. This lesion is partially calcified, demonstrating magnetic susceptibility artifact corresponding to CT findings. There is the suggestion of subtle rim enhancement along the posterior aspect of the lesion, although no internal enhancing component is identified. The left VII/VIII nerve complex is compressed and displaced posteriorly as it exits the brainstem and courses in the cerebellopontine angle cistern.
Case Discussion
Upon further investigation, it was gathered that the patient had undergone microvascular decompression of left cranial nerve VII in 1992 for hemifacial spasm due to vertebrobasilar dolichoectasia. Therefore, the combination of imaging findings in this case represent Teflon felt/pad used in the decompression, and likely a partially calcified Teflon granuloma with recurrence of symptoms. Teflon granulomas may enhance, especially early on, although this is not the rule. Although there was no associated enhancement, the patient was treated with high-dose steroids in an attempt to curb any ongoing inflammatory response and decrease mass effect.