Case 16
History:
16 year old male with progressive painless right orbital swelling and exophthalmos
Findings:
Orbital MRI examination showing an extensive enhancing right orbital mass extending into the ipsilateral cavernous sinus. Note that the orbital wall is expanded but not destroyed. Also note asymmetrical thickening of the subcutaneous soft tissues of the right face.
Diagnosis:
Plexiform neurofibroma (PN)
Discussion:
Plexiform neurofibroma (PN) is a locally aggressive congenital lesion only encountered in patients with NF1. Composed of disorganized schwan cells, neurons and collagen. PN tend to grow along the nerve of origin into the intracranial space. They can involve multiple nerve fascicles and is usually very vascular, rendering surgical excision very difficult. On both CT and MRI Plexiform neurofibroma appears as a mass arising around the orbital apex or superior orbital fissure. They are heterogenous on MRI with variable contrast enhancement. Patients with NF1 and orbital lesions are typically followed every 3 to 6 months.
