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A Rare Presentation and Challenging Reconstruction
of an Extensive Cystic Orbital Schwannoma
Authors:
Son T. Ho MD, 1 Ophthalmology resident
Vikram Premkumar BA, 1 Medical student
Enrique Palacios, MD, 2 Staff radiologist
Alejandra A. Valenzuela MD, 1 Staff ophthalmologist
Institutional affiliation:
1
Department of Ophthalmology, Tulane University School of Medicine, New Orleans,
Louisiana, USA
2
Department of Radiology, Tulane University School of Medicine, New Orleans,
Louisiana, USA
Corresponding author:
Dr. Alejandra A. Valenzuela, MD
1430 Tulane Ave, SL-69, New Orleans, LA, 70112 USA
Phone 1 (504) 988 2465
Fax: 1 (504) 988 2684
Proprietary interest statement:
The authors have no proprietary interests in any of the products mentioned in this paper.
Abstract
A 57 year-old female presents with an irritated right eye and right-sided enophthalmos
with hypoglobus for the past year. The patient previously had an extensive right-sided
cystic orbital schwannoma removed with orbital reconstruction 5 years ago. Imaging
revealed an enlarged right orbit with medial wall collapse and inferior displacement of a
floor plate implant. An anterior orbitotomy with placement of an enophthalmos implant,
three 1mm Medpor sheets, an orbital rim implant, and an oral mucosa graft in inferior
fornix with a lateral strip were used to reconstruct the ocular malposition and right lower
lid retraction. We report a successful case of a complex orbital reconstruction in a patient
with orbital deformity subsequent the removal of a massive cystic schwannoma.
Key Words
scwhannoma, orbital reconstruction, enophthalmos, orbital implant, lid retraction
Introduction
Primary orbital schwannoma (POS) comprises 1% of all orbital tumors and are typically
slow growing and benign.1 They arise from the peripheral nervous system and are
asymptomatic when small but if large can present as an anterior orbital mass with optic
neuropathy, proptosis, diplopia, and sinusitis.2,3 Massive tumors involving the orbit are
often in close proximity to the cranium and sinuses, requiring extensive and meticulous
dissection along with challenging reconstruction. This case highlights an extensive POS
and the subsequent reconstruction after primary intervention by neurosurgery and
otolaryngology.
Case Report
A 57 year-old African-American female was referred for right ocular surface discomfort,
severe right enophthalmos, and hypoglobus evaluation. Her past medical history is
significant for a massive well-circumscribed right orbital cystic schwannoma, that
extended from the right cavernous sinus into the superior orbital fissure superiorly, the
foramen rotundum inferiorly, and through the lamina papyracea into the sinuses medially
(Figure 1a). Surgical removal of the tumor with only partial orbital reconstruction was
performed 5 years prior with no evidence of tumor recurrence. On examination, the right
eye had no light perception, presented a relative afferent pupillary defect, and optic nerve
atrophy. There was significant ocular surface dessication, in keeping with a 10 mm
lagophthalmos and cicatricial lower lid retraction. In addition, she had a large angle right
sensorial exotropia, as well as limitation in adduction and elevation of the right globe.
Naugle exophthalmometry measurements revealed 13mm on the right and 28 mm on the
left, with 7mm right hypoglobus. Extra-ocular movement and anatomical position was
normal in her left eye.
An orbital CT and MRI showed a partially reconstructed right orbit displaying significant
orbital volume discrepancy due to an enlarged and disrupted orbit. Orbital abnormalities
included: a metallic mesh in the right frontal bone after the craniotomy resulting in a
disrupted roof, a posterior displaced lateral orbital rim with most of the greater wing of
the sphenoid absent (Figure 1b), a metallic mesh acting as the orbital floor was placed
lower than the anatomical position of the left orbit, and a collapsed medial orbital wall.
A management plan was designed in a step-wise fashion and the patient underwent four
surgical procedures to address the different problems. Globe position was initially
addressed by an anterior orbitotomy with an inferior fornix approach. A large right
enophthalmos Medpor implant (22x31x7mm) was inserted along with three trimmed
1mm thickness Medpor sheaths positioned between the enophthalmos implant and the
previously reconstructed metallic floor mesh (Figure 2a-b). Care was taken to ensure no
worsening of the restriction on the elevation of the globe. Post-operative
exophthalmometry readings showed symmetric 28mm with a residual 1.5 mm right
hypoglobus. The patient then underwent strabismus surgery to correct her 35 PD sensory
exotropia. At the same time a 20x8mm scleral spacer was inserted in the right lower lid.
The third procedure involved the insertion of an infer-lateral Medpor orbital rim implant
(30x40x8.45mm) (Figure 2c) and the reconstruction of inferior crus of the lateral canthal
tendon with a tarso-conjunctival graft from the contralateral upper lid. The graft was
anchored in with a screw to the newly inserted rim correcting the remaining hypoglobus
and lid malposition. The last surgery involved excising extensive scar tissue that was
impairing the right lower lid to move beyond the orbital rim. In addition, the mechanical
lagophthalmos was improved by inserting a hard-palate mucosa graft into the inferior
fornix. The patient tolerated the surgeries well and without complications. Symptoms
related to corneal exposure are minimal and the patient has an excellent cosmetic result.
Discussion
POS are rare tumors and their origin can be identified only half the time, arising from the
branches of the oculomotor, trochlear, trigeminal, and abducens nerves, as well as, from
sympathetic and parasympathetic fibers, but most originate from first division of the
trigeminal ganglion (supratrochlear and supraorbital branch).2,4 Clinical presentation is
often dictated by tumor size and includes: slowly progressive proptosis, globe
displacement, dysfunction of ocular motility, and diplopia. Progressive growth can cause
compression of the optic nerve with papilledema or optic atrophy. Although mostly
benign, POS can cause bone erosion with widening of the superior orbital fissure,
expansion of the orbit, as well as destruction of the orbital wall invading the maxillary
sinus and nasal cavity in the case of local extension.5
CT and MRI provide useful information on tumor size, characteristics, location within the
orbit and extension into neighboring tissues.3 CT normally shows a round, encapsulated,
well-defined hypodense, lesion. However, cystic degeneration is not uncommon in long
standing lesions. 6,7 MRI is generally limited by anatomical variation of the lesion, but
has use for soft tissue delineation and changes in the lesion over time.8 Ultimately, and as
most tumors in the orbit, the key in the diagnosis is the histopathology confirmation.
Classically, the tumor shows two distinct patterns of spindle cell arrangement: the solid
and cellular Antoni type A, and the less cellular Antoni B pattern with myxoid areas.
Degenerative cystic changes in old lesions are secondary to coalescence of mucinous or
microcystic areas in a predominance of Antoni B tissue.4
The treatment of choice is the complete surgical resection. The presentation of our patient
is unique because of the wide involvement of several anatomical structures. The lack of
reconstruction in the initial attempt to remove this large mass led to blindness, sensory
strabismus, an enlarged orbit with globe malposition, and corneal exposure due to
lagophthalmos. The challenging and intricate reconstruction required consecutively
staged surgeries led to a remarkable cosmetic outcome and resolution of the
enophthalmos, lid, and globe malposition (Figure 3).
Our case focuses on the presentation of an extensive POS and the subsequent
reconstruction of the orbit after primary surgical intervention. Furthermore, continual
follow up after major surgical procedures and reconstruction for POS can prevent and
address symptomatic and cosmetic complications that can arise.
Figure 1: (a) Axial CT scan during initial presentation showing the well-circumscribed
right orbital cystic schwannoma extending from the cavernous sinus into the superior
orbital fissure and through the lamina papyracea into the sinuses medially. (b) An
preoperative axial CT showing medial wall compromise and the absence of the lateral
orbital rim and greater wing of the sphenoid (arrow).
Figure 2: (a) A coronal CT after her first surgery, showing a Medpor enophthalmos
implant and three Medpor sheets piled on top of it on the right orbital floor (arrow). (b)
An axial CT showing a Medpor enophthalmos implant in the right orbit. (c) Intraoperative image of the orbital rim Medpor implant insertion in the patient’s third
reconstructive surgery.
Figure 3: Initial presentation of the patient to demonstrating severe right enophthalmos,
exotropia, and hypoglobus. Post-operative photo, one week after her last surgery,
showing a good cosmetic result and resolution of orbital and lid abnormalities.
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