Plexiform neurofibroma infiltrating the facial nerve

Area of Science:

• Neuropathology
• Oncology

Background:

• Plexiform neurofibromas typically present as circumscribed masses compressing nerves.
• Facial nerve involvement by neurofibroma can lead to significant functional deficits.

Observation:

• A unique case of plexiform neurofibroma extensively infiltrating the left facial nerve trunk and branches was observed.
• The infiltration occurred without compromising facial nerve function, deviating from the typical compressive mass presentation.

Findings:

• Histologic examination revealed diffuse involvement of even small facial nerve branches.
• Electron microscopy identified Schwann cell and fibroblast proliferation within a collagenous matrix.
• Collagen synthesis was attributed to fibroblasts, not Schwann cells, and many Schwann cells were detached from axons.

Implications:

• This suggests a potential detachment of Schwann cell function in neurofibroma formation.
• Understanding this infiltration pattern may inform future diagnostic and therapeutic strategies for facial nerve neurofibromas.