Isolated peripheral nerve sheath tumours of the orbit.

Fifty-four cases of peripheral nerve sheath tumours within the orbit are reviewed. Benign neurilemmomas or neurofibromas occurred in 93% of patients and had an equal incidence. There was a family history or other signs of systemic neurofibromatosis in one-quarter of those with solitary neurofibromas, but in none of the patients with neurilemmoma. Symptoms and signs were generally those of an orbital mass lesion and pain or sensory loss was unusual, occurring more frequently with malignancy. Within the orbit, most peripheral nerve sheath tumours affect the first division of the trigeminal nerve and extension of some tumours through the superior orbital fissure limits their surgical resection. Despite incomplete resection of some tumours, with up to 23 years follow-up there have been no recurrences requiring further surgery. A postoperative sensory deficit occurred in only 32% of patients with benign neurilemmomas and 72% with neurofibromas.