Polytetrafluoroethylene-induced granuloma and brainstem cyst after microvascular decompression for trigeminal neuralgia: case report.

Objective: Microvascular decompression is commonly performed for medically refractory trigeminal neuralgia. A piece of polytetrafluoroethylene (PTFE) is usually placed between the trigeminal nerve and the blood vessel causing the compression. The procedure is effective and relatively safe, and PTFE is presumed to be inert. Reactions to PTFE are rare.

Clinical Presentation: We report a patient who developed progressive neurological symptoms 5 years after microvascular decompression surgery. Imaging showed an enhancing cerebellopontine mass resembling a posterior fossa tumor with a large cyst compressing the brainstem.

Intervention: Craniotomy was performed to decompress the cyst. Biopsy of the enhancing mass showed granulomatous inflammation. The patient underwent a second brainstem decompression surgery with placement of a catheter in the cyst connected to an Ommaya reservoir; she has moderate to severe residual neurological deficits.

Conclusion: This may be the first case of a severely disabling, space-occupying cyst resulting from a reaction to intracranial PTFE. Should this exceptionally rare complication be disclosed to patients or is it an idiosyncratic reaction unlikely to occur again?