Trigeminal malignant peripheral nerve-sheath tumor: Systematic review, and case report treated by proton-beam therapy

Malignant peripheral nerve-sheath tumor (MPNST) is rare, occurring in approximately 0.001% of the general population. Cases involving cranial nerves, and particularly the trigeminal nerve (V), are exceptionally rare, with only 36 cases reported in a literature review in 2013. Standardized treatment and follow-up protocols are lacking. Here, we present a case of MPNST of the trigeminal nerve, provide a review of all cases described in the literature, and discuss treatment, surgical approach, recurrence rate, follow-up time and prognosis.

Based on PRISMA guidelines, we reviewed all cases of trigeminal MPNST published between 1950 and September 2023. We analyzed risk factors for recurrence. And we report the case of a patient with trigeminal MPNST admitted to our hospital.

The literature review retrieved 39 relevant studies, reporting 48 cases. Patient age ranged from 4 to 71 years, for a mean 44.4 ± 17 years. The male:female ratio was 3.8:1. Most cases developed sporadically; 1 patient had neurofibromatosis type 1 and 1 had type 2. Surgery was the first-line treatment (85%), and radiotherapy was often included as adjuvant (65%). During a mean follow-up of 23.1 ± 24.4 months, fatal outcomes occurred in approximately 30% of patients. Only 1 case of systemic metastasis was reported. The only prognostic factor significantly associated with a lower rate of recurrence was complete surgical resection (p = 0.0035).

Cranial nerve MPNST is extremely rare, and trigeminal MPNST is even rarer. Treatment corresponds to current recommendations for intracranial MPNST, in which radical resection with adjuvant radiotherapy under stereotactic conditions results in the best outcome. Because of the high risk of recurrence, especially in case of incomplete resection, close follow-up is mandatory. Proton-beam therapy could be an interesting alternative adjuvant therapy after surgery.