Trigeminal neuralgia secondary to vascular compression and neurocysticercosis: illustrative case

Abstract

Background: Trigeminal neuralgia (TN) is a frequent neurosurgical problem negatively influencing the quality of life of patients. The standard surgical treatment is microvascular decompression for primary cases and decompression of the mass effect, mainly tumors, for secondary cases. Neurocysticercosis (NCC) in the cerebellopontine angle is a rare etiology of TN. The authors report a case in which NCC cysts around the trigeminal nerve coexisted with a vascular loop, which compressed the exit of the trigeminal nerve from the pons.

Observations: A 78-year-old woman presented with a 3-year history of persistent severe pain in the left side of her face, refractory to medical treatment. On gadolinium-enhanced magnetic resonance imaging, cystic lesions were observed around the left trigeminal nerve and a vascular loop was also present and in contact with the nerve. A retrosigmoid approach for cyst excision plus microvascular decompression of the trigeminal nerve was successfully performed. There were no complications. The patient was discharged without facial pain.

Lessons: Albeit rare, TN secondary to NCC cysts should be considered in the differential diagnosis in NCC-endemic regions. In this case, the cause of the neuralgia was probably both problems, because when both were treated, the patient improved.

Keywords: Peru; microvascular compression; neurocysticercosis; retrosigmoid approach; trigeminal neuralgia.

FIG. 1.

Preoperative axial MRI. A and B: FIESTA sequences showing subarachnoid cystic lesions in the left cerebellopontine angle (yellow arrows) medial and lateral to the trigeminal nerve, which is elongated laterally. C: FLAIR sequence demonstrating hyperintensity (white arrow) in the pial plane of the pons around cysts. D: Gadolinium-enhanced, T1-weighted sequence showing a branch of the AICA at the exit of the trigeminal nerve from (red arrows).

FIG. 2.

Intraoperative images, first stage. A: Initial view of the left cerebellopontine angle, with yellowish and thick arachnoids (yellow arrow). B–F: Identification and complete resection of NCC cysts (light blue arrows) around the trigeminal nerve.

FIG. 3.

Intraoperative images, second stage. A: Initial view after extracting cysts, from the medial and lateral region of the trigeminal nerve (V), toward its exit point of the AICA pons branch (red arrow). B: After microsurgical dissection, the AICA branch of the trigeminal nerve is separated (red arrow). C: Placement of a piece of Teflon (T) between the vascular loop and the trigeminal nerve (red arrow). D: Final view of the trigeminal nerve free of any vascular compression or arachnoid adhesions. C = cerebellum.

FIG. 4.

Postoperative axial MRI. A–C: Axial FIESTA sequences showing the trigeminal nerve is now free of compression by the arterial loop (red arrow) and recovered its usual course, with Teflon fragments (green arrows) around it, and the absence of cystic lesions. D: In the FLAIR sequence, the pial pons hyperintensity (white arrow) persists.