Bevacizumab induces regression of vestibular schwannomas in patients with neurofibromatosis type 2

Abstract

Bilateral vestibular schwannomas are the hallmark of neurofibromatosis type 2 (NF2), and these tumors impair hearing and frequently lead to deafness. Neurosurgical intervention, the only established treatment, often damages the vestibular nerve. We report 2 cases in which treatment with bevacizumab (for 3 months in one case and 6 months in the other) induced regression of progressive vestibular schwannomas by more than 40% and substantially improved hearing in the patient treated for 6 months. Bevacizumab therapy may thus provide an effective treatment for progressive vestibular schwannomas in patients with NF2.

Fig. 1.

Cranial (A and B) and spinal (C and D) MRIs of patient 1 before (A and C) and 6 months after (B and D) bevacizumab treatment. Homogeneous contrast enhancement revealed vestibular schwannoma in the cerebellarpontine angle compressing the brain stem and the 4th ventricle before treatment (A), which was substantially decreased after 6 months of treatment (B). Cervical spine MRI showed a syrinx associated with the intramedullary tumor (suspected ependymoma) before treatment (C), which was visibly decreased 6 months after the start of treatment (D).

Fig. 2.

Hearing of patient 1 before (thin lines) and after 6 months of treatment (thick lines). (A) Pure-tone audiometry. Solid and dotted lines are measures of the middle and inner ear, respectively, (B) Freiburg speech audiogram. The y-scale on the left refers to the speech level for the monosyllabic word test, whereas that in the middle refers to the speech level for numbers. The upper 2 thin lines are reference values for number and monosyllabic word recognition, respectively.

Fig. 3.

Cranial MRI for patient 2 before (A) and 3 months after (B) treatment. The cystic component of the right vestibular schwannoma regressed substantially, whereas mitigation of the associated brain stem compression was clearly seen.