Timothy James Beckman
Purpose:To study the presentation, imaging findings, surgical approach and outcomes in histopathologically proven orbital peripheral nerve sheath tumours.
Methods:A longitudinal, retrospective review of 20 patients who presented between 1988 and 2014 was completed by assessing appropriate charts. Clinical, radiological, surgical and pathological data were analysed.
Results:Patient population included 9 males and 11 females, with mean age of 43.5.
Duration of symptoms at presentation averaged 11 months, with the majority of cases presenting with painless (12, 60%) proptosis (10, 50%). A mass-lesion was the primary complaint for 25% (5), and 35% (7) had a painful presentation. Visual disturbances were described in only 4 cases (20%).
Imaging with CT+/-MRI was performed pre-operatively. The lesions were intraconal (8, 40%) and extraconal (9, 45%), with 4 (20%) showing intracranial extension.
11 lateral orbitotomies and 5 anterior lid crease incisions were performed. 4 with intracranial extension required pteronial transfrontal craniotomies, 2 of which had prior biopsy proven schwannoma. One exenteration was carried out for a malignant PNST.
14 cases were histopathologically reported as orbital schwannoma. A mixed neurofibroma and neurilemmoma was also excised. Only two solitary neurofibroma’s were identified; and a solitary case of malignant PNST required exenteration.
Conclusion:Peripheral nerve sheath tumours of the orbit should be a considered differential-diagnosis when investigating both intraconal and extraconal lesions. The most common presentation of unilateral, painless proptosis, should trigger radiological investigation and specialist opinion. Biopsy and resection of orbital schwannomas generally allowed complete removal with limited complications. Prognosis in this series was good for both benign and malignant lesions.