T1 post-gad T1 post-gad with fat sat T2

Diagnosis: Plexiform neurofibroma

Plexiform neurofibroma, although usually thought of in association with neuro fibromatosis type I, may be sporadic. They are highly vascular, infiltrative tumors which are impossible to remove completely. In the orbit they are associated with the ophthalmic division of the trigeminal nerve. It may have intraconal and extraconal components and may spread intracranially or into the deep face. On imaging they appear as enhancing, lobulated infiltrative lesions typically resulting in proptosis. The optic nerve may be engulfed by the tumor and is always displaced. Due to the characteristic appearance of plexiform neurofibroma, the differential is limited. Other entities to consider are lymphoma, hemangiopericytoma, and metastasis.

This patient did not have known neurofibromatosis. This lesion has been present since childhood and has status post multiple subtotal resections in the past. Of note this patient has a history of fibrous dysplasia involving the ileum. Related Cases

Mafee MF, Putterman A, Valvassori GE, et al. Orbital space occupying lesions: role of CT and MRI, analysis of 145 cases. RSNA, 1987; 25:529-559.

Forbes G. Radiologic evaluation of orbital tumors. Clin Neurosurg, 1985; 32(1): p474-513.

Optic nerve meningioma Orbital lymphoma Optic nerve glioma