Abstract
Background and Importance Optic nerve gliomas (ONGs) are benign and slow-growing tumors with a variable clinical course that may result in significant morbidity. The variability in tumor burden, challenging anatomy, and associated symptomatology require an individualized and multidisciplinary approach. The relative paucity of cases and variation in surgical anatomy prompt the need for accrual of cases in literature to advance the understanding of surgical techniques to address this rare clinical entity.
Clinical Presentation A 19-year-old patient presented with severe and globe-threatening left eye proptosis, negatively affecting quality of life, due to a sporadic intraorbital ONG that had been inexorably growing over the previous 9 years, despite chemotherapy. The patient was taken to the operating room for a single-stage globe-sparing transorbital resection of the intraorbital ONG. The surgical plan consisted of an endoscopic endonasal approach for medial and inferior orbital wall decompression combined with an open lateral orbitotomy, via a lateral canthal incision, for subtotal piecemeal tumor resection to relieve the proptosis, restore alignment of the globe, and yield tissue for molecular analysis. The patient experienced profound improvement in quality of life and opted for radiographic surveillance that has been stable at 5 years.
Discussion and Conclusion Surgical approaches to intraorbital tumors have included both transcranial and/or transorbital routes, with the latter more recently encompassing endoscopic endonasal techniques. This report presents the use of a novel combination of transorbital techniques for resection of an intraorbital ONG with severe proptosis, including an endoscopic endonasal approach combined with an open lateral orbitotomy.
Keywords: eye proptosis, optic nerve glioma, transorbital, endoscopic endonasal, lateral orbitotomy
Background and Importance
Optic pathway gliomas (OPGs) represent 1% of intracranial tumors. 1 2 In approximately 50–60% of cases, OPGs are associated with neurofibromatosis type 1, whereas the remainder are sporadic. 1 2 Sporadic cases have a greater tendency to become symptomatic and/or progress, with 90% of patients ultimately requiring treatment. 3 Optic nerve gliomas (ONGs) constitute 30 to 35% of OPGs and are limited to the intraorbital optic nerve. The remainder of OPGs may involve the optic chiasm and/or tracts, extending to the brainstem and/or hypothalamus. 1 ONGs are typically low-grade, with pilocytic astrocytoma World Health Organization (WHO) grade 1 being the most common pathological entity. 4 Increased understanding in their molecular underpinnings has led to the availability of targeted agents, such as RAF and MEK inhibitors, in addition to mTOR, VEGF, and NTRK agents. 3 Although benign and usually slow growing, their clinical course can be variable and may result in significant morbidity. 5
Management options include observation versus treatment that can consist of pharmacological cancer-directed therapy (chemotherapy and/or targeted therapy), radiation therapy, and surgical resection. The variability of tumor burden, challenging anatomy, and associated symptomatology require an individualized and multidisciplinary approach. Pharmacological cancer-directed therapy and radiation therapy are the current mainstays of treatment, with surgical intervention reserved for cases with globe-threatening proptosis, risk of additional visual loss, hydrocephalus, and/or cortical mass effect, in addition to diagnostic uncertainty. The relative paucity of cases and variation in surgical anatomy limit consensus and prompt the need for accrual of cases in literature to advance the understanding of surgical intervention for this rare clinical entity.
This report presents a novel combination of transorbital techniques used for resection of an intraorbital ONG that presented with globe-threatening proptosis and reviews the relevant literature.
Clinical Presentation
Preoperative
A 19-year-old patient presented to the neurosurgery clinic with severe left eye proptosis negatively affecting the patient’s quality of life, due to a sporadic OPG that had been inexorably growing over the previous 9 years. The tumor had been incidentally revealed during evaluation for hearing loss. At that time, the ONG was fully intraorbital and then continued to grow both posteriorly and superiorly despite two rounds of chemotherapy. Magnetic resonance imaging (MRI) confirmed that an intraorbital contrast-enhancing lesion consistent with an ONG was causing the severe left eye proptosis ( Fig. 1A ). Globe protrusion of the affected eye was 3.4 cm measured from the interzygomatic line to the anterior aspect of the globe on the MRI, analogous to the measurement from Hertel’s exophthalmometer, significantly more than the nonaffected eye that was 1.6 cm ( Fig. 1A ). Computed tomography (CT) revealed bony remodeling, consistent with a long-standing process ( Fig. 1B ). Physical exam revealed severe proptosis of the left eye with thinning of the eyelid ( Fig. 1C ). Visual acuity in the affected eye was down to light perception only. There were also superior temporal, inferior temporal, superior nasal, and inferior nasal visual defects. On slit-lamp examination, the patient had thin upper lid that closed over the affected eye with moderate lag. There was a trace injection of the sclera along with superficial punctate keratitis. Fundoscopic examination showed disc pallor. Management options were discussed, including continued observation versus treatment with cancer-directed pharmacological therapy, radiation therapy, and/or surgery. The patient’s goals of care were to relieve the eye proptosis, preserve the globe, and minimize risk. After thoughtful consideration in a shared decision-making manner, the plan was made to proceed with surgical intervention focused on reduction of the intraorbital tumor burden to relieve the symptomatic eye-threatening proptosis, while providing tumor tissue for molecular analysis to identify possible targeted agents for subsequent pharmacological therapy. This prompted the design of a single-stage globe-sparing transorbital approach for resection of the ONG, requiring multidisciplinary and close collaboration between the neurosurgery, oculoplastic surgery, and otolaryngology services.
Fig. 1.
Preoperative radiographic and clinical images. ( A ) MRI brain with and without contrast demonstrates an enhancing intraorbital mass centered around the optic nerve, consistent with an optic nerve glioma (ONG), measuring 2.6 × 2.6 × 2.5 cm in the anteroposterior, transverse, and craniocaudal directions. There was a protrusion of the globe in the affected eye by 3.4 cm, as measured from the interzygomatic line (dotted purple line) to the anterior surface of the globe (dotted green line), analogous to Hertel’s exophthalmometer measurement. This is 1.8 cm more than the regular eye on the right, where the corresponding distance is 1.6 cm (dotted red line). (B) CT head without contrast is consistent with the MRI and reveals smooth remodeling (*) of the superior orbital fissure and the optic canal. (C) Clinical photograph demonstrating the severe left eye proptosis. CT, computed tomography; MRI, magnetic resonance imaging.
Operative
The surgical approach included an endoscopic endonasal approach for medial and inferior orbital wall decompression combined with an open lateral orbitotomy for tumor resection ( Fig. 2 ). After appropriate preparation of the corneal surface and identification and marking of the medial and lateral recti muscles, we performed the endoscopic endonasal portion of the case. This comprised medial and inferior wall decompression of the orbit to facilitate manipulation of the orbital contents and provide a route for orbital volume expansion. Then, we proceeded with an open lateral orbitotomy, via a lateral canthal incision. After cantholysis of the inferior and superior crus of the lateral tarsal tendon, as well as exposure and medial retraction of the periorbita of the lateral orbital rim, we opened the periorbita superiorly and inferiorly to the lateral rectus muscle. We used ribbon retractors to protect the globe and palpate the underlying tumor mass, as well as protect the lateral rectus muscle, during the tumor resection. Then, we dissected through the fat and identified a firm underlying tumor, without need for bone resection of the orbital rim. We used tenotomy scissors to open the tumor capsule, revealing soft tumor within. We then performed a piecemeal subtotal resection of the tumor with pituitary and tumor forceps to achieve resolution of the proptosis while preserving the optic nerve and ophthalmic artery. After achieving hemostasis, we closed the lateral orbital periorbita, reconstructed the lateral canthal angle and tendon, and closed the skin in standard fashion. We regularly checked the pupil during the procedure to ensure the absence of significant mydriasis from prolonged pressure. The patient tolerated the procedure well and was discharged the following day. Pathology revealed a pilocytic astrocytoma WHO grade 1 with BRAF-KIAA1549 fusion.
Fig. 2.
Schematic of the operative plan. The operative plan was a single-stage transorbital approach for resection of an intraorbital ONG to relieve severe eye proptosis. The transorbital approach consisted of an endoscopic endonasal approach for medial and inferior orbital wall decompression, combined with an open lateral orbitotomy, for tumor resection without need for orbital rim resection. Tumor resection was performed in piecemeal fashion, after incision of the tumor capsule, to achieve resolution of the proptosis while preserving the optic nerve and ophthalmic artery. This required close and multidisciplinary collaboration between the neurosurgery, oculoplastic surgery, and otolaryngology services. ONG, optic nerve glioma.
Postoperative
At the patient’s immediate postoperative visit, there was expected eye swelling that mostly resolved by around 6 weeks. The patient had no pain in her eye. Her visual acuity and fields were stable. The patient had mild ptosis with good levator function, and mild reduction in a subset of extraocular movements (downgaze, left gaze, levodepression, and levoelevation). The patient gradually improved with respect to her ptosis and extraocular movements. The proptosis remained resolved. She had an excellent cosmetic result and experienced profound improvement in her quality of life. Short-term follow-up at less than 6 months ( Fig. 3A ) revealed stable resolution of the proptosis, both on imaging and on clinical exam. Long-term follow-up greater than 6 months ( Fig. 3B ), revealed that the patient’s residual tumor burden remained stable, as did the associated alignment of the globe. She declined adjuvant ONG treatment, favoring serial imaging that has now been stable for 5 years.
Fig. 3.
Postoperative radiographic and clinical images. (A) Short-term follow-up of less than 6 months. The top panel includes an axial T1 with contrast image from a postoperative MRI performed at around 4 months after surgery showing significant reduction of the intraorbital tumor volume with resolution of the proptosis in the affected eye. The bottom panel includes a clinical picture taken around the same time, demonstrating persistent resolution of the proptosis and mild ptosis of the lid with good levator function. (B) Long-term follow-up greater than 6 months. The top panel includes an axial T1 with contrast image from a postoperative MRI performed at around 3 years after surgery showing stable residual intraorbital tumor. The bottom panel includes a clinical picture taken around 8 months after surgery, demonstrating persistent resolution of the proptosis and mild ptosis of the lid. Repeat imaging has been stable for 5 years. MRI, magnetic resonance imaging.
Discussion and Conclusion
Surgical approaches to intraorbital lesions include open transcranial and/or transorbital techniques. 6 7 8 While endoscopic endonasal approaches are frequently used for ocular pathologies setting of thyroid disease, traumatic orbital fractures, and/or optic neuropathies, they have been increasingly recognized as useful adjuncts for selected intraorbital tumors. 9
To place our surgical approach in a broader context, cases of intraorbital ONG resections were abstracted from reports in the literature where the surgical approach for resection could be identified, the extent of the planned ONG resection was limited to the orbit, and pathology was clearly stated. Notably, intraorbital ONGs represented a small subset of cases in reports describing surgical approaches for resection of intraorbital ONGs, whereas reports dedicated to outcomes of intraorbital ONGs frequently did not specify surgical approach, reducing the overall number of cases abstracted from the literature. Of the total cases identified, 81% (98/121) were performed primarily via a transcranial surgical approach, as summarized in Table 1 , 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 with only three cases combined with an open transorbital approach consisting of a lateral orbitotomy. 13 The remainder of cases, 19% (25/121), were performed via transorbital approaches, as summarized in Table 2 . 13 25 26 27 28 29 30 31 Within transorbital approaches, the majority (18/25) of cases were performed via open approaches, with the lateral orbitotomy the most frequent by far (17/18). Endoscopic endonasal approaches were utilized in 7/25 or 28% of transorbital cases. The majority of endoscopic endonasal cases were done in combination with open transorbital approaches, including five combined with a transconjunctival approach 29 and one combined with a retrocaruncular approach. 30 There was only one report of a purely endoscopic endonasal approach. 31 Piecemeal resection of ONGs reportedly has fewer complications than en bloc resections, whether performed via the transcranial 23 and/or transorbital 26 approaches.
Table 1. Summary of cases abstracted from the literature of intraorbital optic nerve glioma resections via transcranial approaches (totaling 96 cases).
| Type of transcranial approach | Total number of patients per approach | Total number of patients per reference | Operative nuances and/or annotations per reference | References |
|---|---|---|---|---|
| Transfrontal | 11 | 2 | Removal of orbital roof (not rim) | Love and Benedict 1945 10 |
| 5 | Removal of orbital roof (not rim) | Love and Dodge 1953 11 | ||
| 1 | Removal of orbital roof (not rim) | Housepian 1969 12 | ||
| 3 | Removal of orbital roof (not rim), combined with transorbital lateral orbitotomy | Bilgic et al 1989 13 | ||
| Supraorbital | 27 | 5 | Removal of orbital rim, roof, and lateral wall, as unit with frontal bone | Benes et al 1990 14 |
| 11 | Removal of orbital rim, roof, and lateral wall, as unit with frontal bone | Shriver et al 2012 15 | ||
| 10 | 8 cases: removal of orbital roof (not rim) 2 cases: removal of orbital rim and roof | Zipfeil et al 2022 16 | ||
| 1 | Removal of orbital roof and rim | Xie et al 2024 17 | ||
| Frontotemporal | 58 | 1 | Removal of orbital roof and rim | Miyamoto et al 2006 18 |
| 2 | Removal of orbital roof (not rim) and wall | Liu et al 2012 19 | ||
| 1 | Removal of orbital roof (not rim) and wall, and subsequent enucleation | Loh et al 2015 20 | ||
| 4 | Removal of orbital roof and lateral wall (not rim) | Borghei-Razavi et al 2017 21 | ||
| 1 | Removal of orbital roof (not rim) and lateral wall | Fredrickson et al 2022 22 | ||
| 48 | Removal of orbital roof and rim, including 24 cases: en-bloc resection 24 cases: piecemeal resection after incision of capsule | Yang et al 2023 23 | ||
| 1 | Removal of orbital roof and rim | Alvarez et al 2025 24 |
Table 2. Summary of cases abstracted from the literature of intraorbital optic nerve glioma resections via transorbital approaches (totaling 25 cases).
| Type of transorbital approach | Total number of patients per approach | Total number of patients per reference | Operative nuances and/or annotations per reference | References |
|---|---|---|---|---|
| Lateral orbitotomy | 17 | 5 | Removal of lateral orbital wall (not rim), modified Kronlein | Bilgic et al 1989 13 |
| 1 | Removal of lateral orbital wall and rim, lateral eyebrow incision | Kondo et al 2019 25 | ||
| 10 | Removal of lateral orbital wall and rim, lateral lid crease incision 5 cases: en-bloc resection 5 cases: piecemeal resection after capsule incision | Mohammad 2020 26 | ||
| 1 | Superolateral orbitotomy, infraciliary incision, no bone removal | Apanisile and Karosi 2017 27 | ||
| Anterior orbitotomy | 1 | 1 | Lid-sparing exenteration of orbit, including enucleation, with transorbital endoscopic assistance | Maseko et al 2025 28 |
| Endoscopic approaches | 7 | 5 | Endonasal transethmoidal removal of medial orbital wall, combined with open transconjunctival approach, en bloc resection, no bony reconstruction | Shi et al 2015 29 |
| 1 | Endonasal transethmoidal removal of medial orbital wall, combined with open retrocaruncular approach, en bloc resection, no bony reconstruction | Lee et al 2022 30 | ||
| 1 | Endonasal transethmoidal removal of medial orbital wall, with bony reconstruction | Zhang et al 2022 31 |
This case report presents a novel combination of transorbital techniques, namely an endoscopic endonasal approach combined with an open lateral orbitotomy for resection of an intraorbital ONG. The medial and inferior wall orbitotomies accomplished via the endoscopic endonasal approach provided decompression of the orbital contents, expansion of the orbital volume, and facilitated resection of the intraorbital tumor via the open lateral orbitotomy without the need for bony resection of the orbital rim. The piecemeal subtotal resection provided sufficient reduction in tumor burden to relieve the proptosis and normalize globe alignment, resulting in profound improvement in the patient’s quality of life. The surgical plan met the patient’s goals of care of relieving the proptosis, preserving the globe, and minimizing surgical risk. It also yielded molecular characterization of the tumor for possible future targeted therapy per patient choice. This approach has thus far provided long-term radiographic tumor control at 5 years.
Footnotes
Conflict of Interest The authors declare that they have no conflict of interest.
Contributors’ Statement E.B.: Conceptualization, Data curation, Investigation, Methodology, Validation, Writing - original draft, Writing - review & editing. A.D.: Conceptualization, Data curation, Investigation, Methodology, Validation, Writing - review & editing. A.D.: Conceptualization, Data curation, Investigation, Methodology, Supervision, Validation, Writing - review & editing.
Informed Consent
Written informed consent was obtained from the patient for publication of this case report and associated clinical and radiographic images.
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