Differential Diagnosis of Acquired Unilateral Orbital Mass

• Vascular
• Cavernous hemangioma (most common benign orbital neoplasm)/li>
• Hemangiopericytoma/li>
• Lymphangioma aka Lymphatic Malformation/li>
• Venous Malformation (i.e. orbital varices)
• AVM
• AV Fistula
• Neural Tumors
• Neurofibroma, Meningioma, Schwannoma, Glioma
• Mesenchymal
• Fibrous histiocytoma, solitary fibrous tumor, fibrous dysplasia, osteoma, dermoid cyst, dermolipoma
• Malignant(rare): Rhabdomyosarcoma, Liposarcoma, Fibrosarcoma, Chondrosarcoma, Osteosarcoma
• Malignancy
• Lymphoma, Invasive sinus (SCC, AdenoCa) or intracranial process, other metastatic disease (most commonly breast and lung)

Additional Investigations

• Patient underwent lateral orbitotomy with bone flap and excision of lesion

Diagnosis

• Orbital Schwannoma

Pathophysiology

• Rare, slow growing, encapsulated (by perineurium) tumor arising from the nerve sheath fascicle of either motor or sensory nerves
• Very rare, accounting for 1% of all tumors in the orbit
• Arises from hyperplasia of myelin producing schwann cellst
• Occurs in isolation, or as part of syndromes such as NF-2, Schwannomatosis, and less commonly NF-1
• Most originate from branches of CN 3,4,5,6, parasympathetics, or sympathetics
• Theoretically cannot occur in CN 1 or 2 because these lack sheaths composed of schwann cells

Treatment

• Surgical excision
• Prevent compression of optic nerve and surrounding or involved cranial nerves
• Incomplete removal can lead to recurrence or intracranial extension
• Decompression
• If resection not possible (i.e. apical tumors)
• Radiation Therapy
• Risk of optic neuropathy, secondary malignancy

Prognosis

• Typically good prognosis with improved VA
• Must monitor for recurrence, malignant transformation
• Recurrence has been noted from days to many years after excision
• Residual or de novo

Deep orbitotomy: Surgical incisions

• Hidden approaches
• Upper lid crease incision
• Caruncular approach
• Conjunctival fornix approach
• Conjunctival peritomy approach
• Lateral canthotomy
• Others:
• Upper lid split
• Lynch incision
• Brow incision
• Kronlein incision

Deep orbitotomy: preferred techniques

• Subperiosteal approach*
• Periosteal release at the lateral canthus
• Bone contouring at the orbital rim (near lacrimal fossa)
• Bone flaps
• Bone flap + bone contouring*
• Retractors (e.g lonestar)*
• Neurosurgical cottonoids*
• Finger palpation*
• Suture traction on orbital mases*
• Cryotherapy probe*
• Medial/lateral combined approach
• Combined neurosurgical approach
• Navigation systems

Deep orbitotomy tips:

• Prepare for the worst: obtain as wide an approach as possible
• Study the anatomy then visualize the relationships
• No cautery in the deep orbit
• Keep fat out of your field as long as possible (subperiosteal approach)
• Have an experienced assistant
• Visualization requires patience

References

• Daras M, Koppel BS, Heise CW, Mazzeo MJ, Poon TP, Duffy KR. Multiple spinal intradural schwannomas in the absence of von Recklinghausen’s disease. Spine (Phila Pa 1976)
• Koktekir BE, Kim HJ, Geske M, Bloomer M, Vagefi R, Kersten RC. Orbital schwannomatosis in the absence of neurofibromatosis. J Craniofac Surg. 2014;25(6):2109-11.
• Delfini R, Missori P, Tarantino R, Ciapetta P, Cantore Surg Neurol. 1996 Feb; 45(2):147-53; discussion 153-4.
• Nagashima H, Yamamoto K, Kawamura A, Nagashima T, Nomura K, Yoshida M. Pediatric orbital schwannoma originating from the oculomotor nerve. J Neurosurg Pediatr. 2012;9(2):165-8.
• Kim MS, Park K, Kim JH, Kim YD, Lee JI. Gamma knife radiosurgery for orbital tumors. Clin Neurol Neurosurg. 2008;110(10):1003-7
• Delfini R, Missori P, Tarantino R, Ciapetta P, Cantore G. Primary benign tumors of the orbital cavity: comparative data in a series of patients with optic nerve glioma, sheath meningioma, or neurinoma. Surg Neurol. 1996;45(2):147-53.
• Brucoli M, Giarda M, Arcuri F, Benech A. A benign isolated schwannoma of the orbit. J Craniofac Surg. 2011;22(6):2372-4.
• Konrad EA, Thiel HJ. Schwannoma of the Orbit. Ophthalmolgica, Basel; 1988. p. 118-27
• Goh AS, Kim YD, Woo KI, Lee JI. Benign orbital apex tumors treated with multisession gamma knife radiosurgery. Ophthalmology. 2013;120(3):635-41.
• Kron M, Bohnsack BL, Archer SM, Mchugh JB, Kahana A. Recurrent orbital schwannomas: clinical course and histopathologic correlation. BMC Ophthalmol. 2012;12:44.
• Khan SN, Sepahdari AR. Orbital masses: CT and MRI of common vascular lesions, benign tumors, and malignancies. Saudi J Ophthalmol. 2012;26(4):373-83.
• Shields JA, Bakewell B, Augsburger JJ, Flanagan JC. Classification and incidence of space-occupying lesions of the orbit. A survey of 645 biopsies. Arch Ophthalmol. 1984;102(11):1606-11.
• Kauser H, Rashid O, Anwar W, Khan S. Orbital oculomotor nerve schwannoma extending to the cavernous sinus: a rare cause of proptosis. J Ophthalmic Vis Res. 2014;9(4):514-6.
• Kim KS, Jung JW, Yoon KC, Kwon YJ, Hwang JH, Lee SY. Schwannoma of the Orbit. Arch Craniofac Surg. 2015;16(2):67-72.
• Yulek F, Demer JL. Isolated schwannoma involving extraocular muscles. J AAPOS. 2016;20(4):343-7.Tezer MS, Ozcan M, Han O, Unal A, Ozlugedik S. Schwannoma originating from the infraorbital nerve: a case report. Auris Nasus Larynx. 2006;33:343–345.
• Konrad EA, Thiel HJ. Schwannoma of the orbit. Ophthalmologica. 1984;188:118–127
• Ribeiro SFT, Queirós T, Amorim JM, Ferreira AM, Sales-sanz M. An Unusual Differential Diagnosis of Orbital Cavernous Hemangioma: Ancient Schwannoma. Case Rep Ophthalmol. 2017;8(2):294-300.

Contact

• Jonathan Kim, MD, Associate Professor of Clinical Ophthalmology, A. Linn Murphree Professor and Director of the Ocular Oncology Service, jonathan.kim@med.usc.edu
• Jennifer Danesh, MD, PGY-2 Ophthalmology resident, jennifer.danesh@med.usc.edu

Section Editors

• Vivek Patel, MD, Associate Professor of Clinical Ophthalmology, Program Director, vivek.patel@med.usc.edu
• Jesse Berry, MD, Assistant Professor of Clinical Ophthalmology, Associate Program Director, jesse.berry@med.usc.edu

Produced by: Monica Chavez, John Daniel, Dr. Vivek Patel and Mellissa Linton