Primary central nervous system amyloidoma involving cranial nerves V and VII: A case report and literature review

Abstract

Background: Amyloidoma is a rare mass lesion formed by abnormal deposition of amyloid proteins. There are 25 reported cases of Meckel's cave amyloidoma primarily involving the trigeminal nerve alone. Case presentation: A 55-year-old woman presented with one year of right-sided trigeminal neuropathy and facial weakness. On examination, there was right-sided V1-V3 dysesthesia and partial right facial paralysis. Magnetic resonance imaging (MRI) showed a right-sided enhancing 1.5 cm × 0.7 cm × 0.4 cm mass in Meckel’s cave. The mastoid segment of the right facial nerve demonstrated focal enhancement. A biopsy of the Meckel’s cave lesion was performed via a right lateral transorbital approach. Results: Histologic sections showed pale eosinophilic amorphous material birefringent to polarized light in Congo red stain. Mass spectrometry confirmed a lambda light chain amyloidoma. Extensive workup did not reveal evidence of systemic amyloidosis, consistent with localized central nervous system (CNS) amyloidoma in Meckel’s cave. The patient remains stable at nine months. Conclusion: This is a rare case of primary Meckel’s cave amyloidoma affecting cranial nerves V and VII. A minimally invasive lateral transorbital approach was employed to access the tumor in the middle cranial fossa. Amyloidoma should be considered in the differential diagnosis of lesions involving Meckel’s cave and multiple cranial nerves.

Keywords

• Amyloidoma
• Meckel’s cave
• Gasserian ganglion
• Trigeminal neuropathy
• Transorbital approach
• Middle cranial fossa