CT findings in orbital tumours of nerve sheath origin

Orbito-cranial schwannoma-a multicentre experience

OBJECTIVES

To describe the features, management approaches, and outcomes of orbito-cranial schwannomas.

METHODS

Retrospective review of ten patients with orbito-cranial schwannomas managed in six orbital services over 22 years. Data collected included demographics, presenting features, neuroimaging characteristics, histology, management approach, complications, and outcomes.

RESULTS

Mean age of the patients was 41.4 ± 19.9 years, and 6 (60%) were females. The majority presented with proptosis (90%), limited extraocular motility (80%), eyelid swelling (60%), and optic neuropathy (60%). Most lesions (80%) involved the entire anterior-posterior span of the orbit, with both intra- and extraconal involvement. All tumours involved the orbital apex, the superior orbital fissure, and extended at least to the cavernous sinus. Surgical resection was performed for all. Seven (70%) of the tumours were completely or subtotally resected combining an intracapsular approach by an orbital-neurosurgical collaboration, with no recurrence on postoperative follow-up (6-186 months). Three underwent tumour debulking. Of these, two remained stable on follow-up (6-34 months) and one showed progression of the residual tumour over 9 years (cellular schwannoma on histology) necessitating stereotactic radiotherapy (SRT) for local control. Adjuncts to the orbito-cranial resection included perioperative frozen section (n = 5), endoscopic transorbital approach (n = 2), and image-guided navigation (n = 1). Post-surgical adjuvant SRT was used in three subjects.

CONCLUSIONS

These results highlight the possibility of successful surgical control in complex orbito-cranial schwannomas. A combined neurosurgical/orbital approach with consideration of an intracapsular resection is recommended. Recurrence may not occur with subtotal excision and observation may be reasonable. Adjunctive SRT for progression or residual tumour can be considered.

Isolated Neurofibroma of the Orbit: Case Report and Literature Review

PURPOSE

To summarize the clinical, radiographic, and intraoperative characteristics of isolated neurofibromas of the orbit (INFO) in the literature and report a case of INFO.

METHODS

Case report and a systematic review of the literature.

RESULTS

A total of 45 patients were identified from 18 previous studies. There was no sex predilection and mean ages were between 32.3 and 40.0 years with a standard deviation of 9.8 to 19.5 years, median age was 32 to 38 years with a range of 1.5 to 82 years. On CT imaging, INFO reveals homogeneous precontrast radiodensity similar to that of extraocular muscles. On MR imaging, INFO appears hypointense to orbital fat and isointense to brain on precontrast T1-weighted images. On T2-weighted images, they have been described as being predominantly hyperintense with possible hypointense intralesional islands. To the best of our knowledge, our case identifies the youngest patient with the myxoid histologic variant of INFO.

CONCLUSIONS

Patients with orbital neurofibromas should be evaluated for the presence of systemic neurofibromatosis, and the plexiform variant is a commonly associated subtype. The myxoid variant can be part of a lesser known condition called NAME syndrome (nevi, atrial myxoma, myxoid neurofibroma, and ephelides) which may warrant echocardiography in patients to evaluate for associated cardiac tumors.

Infra-orbital nerve schwannoma: Report and review

Extra-cranial schwannomas although common in head and neck region are very rarely seen originating from the infra-orbital nerve. We report a case of schwannoma arising from infra-orbital nerve in a 40-year-old male patient. The case presented as an isolated, asymptomatic, slow growing sub-cutaneous nodular swelling over left side of mid-face. On ultrasonography, a localized lesion within the sub-cutaneous tissue of cheek was observed, without involvement of orbital, maxillary sinus or underlying bone. Aspiration biopsy of the lesion showed spindle shaped cells predominantly arranged in Antoni A pattern around verocay bodies, with less organized Antoni B tissue in few places. Diagnosis of schwannoma, probably arising from terminal branch of infra-orbital nerve was established. The tumor was approached through skin incision. At the time of exploration, the lesion was found to emanate from the nerve trunk of peripheral branch of infra-orbital nerve, which was dissected and preserved. We correlate our experience with previously reported cases of infra-orbital nerve schwannoma.

Schwannoma in the anterior orbita

A schwannoma is a rare benign tumour of peripheral nerve origin. We present a case of a 65-year-old woman with a 1-year history of a slowly enlarging, painless and movable mass, palpable by fingers in her right lower eyelid, adjacent to the inferior orbital rim. No apparent mass was present by macroscopic examination. A subciliary incision and blunt dissection through the septum revealed a pearl-like round and encapsulated cystic mass between the fat pads just below the septum. A total excision of the tumour was performed. Histopathology and immunohistochemistry led to the diagnosis of schwannoma. Although rare, schwannoma should be considered in the differential diagnosis of well-capsulated masses in the periorbital region.

Orbital masses: CT and MRI of common vascular lesions, benign tumors, and malignancies

A wide variety of space occupying lesions may be encountered in the orbit. CT and MR imaging frequently help confirm the presence of a mass and define its extent. Characteristic imaging features may help distinguish among lesions that have overlapping clinical presentations. This review focuses on some of the common orbital masses. Common vascular lesions that are reviewed include: capillary (infantile) hemangioma, cavernous hemangioma (solitary encapsulated venous-lymphatic malformation), and lymphangioma (venous-lymphatic malformation). Benign tumors that are reviewed include: optic nerve sheath meningioma, schwannoma, and neurofibroma. Malignancies that are reviewed include: lymphoma, metastasis, rhabdomyosarcoma, and optic glioma. Key imaging features that guide radiological diagnosis are discussed and illustrated.

Clinico-Radiological Spectrum and Management of Orbital Schwannomas: A Tertiary Care Institute Study

Abstract Purpose: The aim is to study clinical presentations, radiological features and outcome in histopathologically proven orbital schwannomas. Methods: A retrospective and longitudinal study of 16 patients between January 1999 and July 2011 was undertaken by reviewing the appropriate charts. Clinical and radiological data of all orbital schwannomas patients were analyzed. Results: Mean age was 28.18 years (range 8-40 years). Of 16 patients, 10 were males and 6 females. Duration of symptoms was chronic in 15(93%). Chief complaints were proptosis in 10(62.5%), eyelid swelling in 5(31%) and eyelid mass lesion in 2(12.5%). This included a rare case of cystic schwannoma with microphthalmos. Mass was extraconal in 11(69%). Radiological findings varied from solid to cystic, intraconal to extraconal, no enhancement to intense enhancement and presence of calcification. Thirteen (81%) were excised via anterior orbitotomy route while fronto-orbital craniotomy was done in 3(19%). Postoperatively, vision improved or remained stable in 15(94%) and worsened in one (6%). Final visual acuity of 6/6 was achieved in 11(69%), 6/9 in 2, 6/36 in one. Conclusions: Schwannomas may mimic a variety of mass lesions in the orbit because of variable clinical or imaging features and should be considered in the differential diagnosis of all well circumscribed orbital lesions.

Recurrent neurofibroma of the orbit

A 55-year-old male patient presented with gradual progressive outward and downward deviation of right eye since last two years, with history of a similar complaint 10 years ago when he was diagnosed as having neurofibroma of the orbit. Computed Tomography imaging revealed a large, multilobulated, heterogeneous, soft tissue density mass lesion in the retro bulbar region on the medial side of right orbit suggestive of a neurofibroma. Excision and histopathology confirmed it to be a recurrence of neurofibroma of the orbit.

Ethmoidal air cell schwannoma presented as a fronto-ethmoidal mucocele

AIM

To report a rare case of a fronto-ethmoidal mucocele secondary to an ethmoidal schwannoma. To our knowledge this is the first reported case of an ethmoidal schwannoma, a tumour of the peripheral nerve sheath originating from an area not believed to contain peripheral nerves that has presented as a fronto-ethmoidal mucocele.

CASE REPORT

Our patient is a 23-year-old male presented with a one-year history of progressive proptosis and vertical diplopia with restriction of upgaze. Orbital imaging demonstrated a mass in the right medial ethmoidal air cells extending to the frontal sinus and orbit, consistent with a mucocele. Patient underwent endonasal decompression of the right fronto-ethmoidal mucocele. Histology confirmed a schwannoma and repeat imaging post-operatively revealed residual mass originating from the ethmoidal air cells. A right upper eyelid skin crease approach anterior orbitotomy was performed to successfully excise the mass via the lamina papyracea. Post-operatively the patient's proptosis and diplopia resolved, with a full range of ocular movements. Post-operative imagining at 3 months did not show any residual tumour.

COMMENT

Mucocele formation may be secondary to an underlying schwannoma obstructing the fronto-ethmoidal foramen. In such cases we recommend an open-sky technique for full visualisation and improved chance of total removal.

A bilobed schwannoma in roof of orbit: a rare case report

In this paper, we report a case of bilobed schwannoma, presented in the roof of orbit arising from supraorbital nerve. A 62-year male presented with a nontender mass in superior part of orbit and eccentric proptosis. Visual acuity and rest of ocular examination were normal. CT scan and MRI orbit revealed an extraconal homogenous bilobed mass, of size 3.5 to 2.5 cms in roof of orbit. Fine needle aspiration cytology was done, which was suggestive of schwannoma a peripheral nerve tumor. Successful surgical excision of intact bilobed schwannoma was done with careful separation and preservation of supraorbital nerve from which it was originated. Postoperative period was uneventful though rare, less than 1%, schwannoma can present as painless mass in the orbit and proptosis. Treatment of choice is surgical excision of intact tumor to prevent recurrence and preservation of peripheral nerve from which it arises.

Orbital neurofibroma presenting with a negative Hounsfield unit on computerized tomography

PURPOSE

To report a case of diffuse orbital neurofibroma which displayed an unusual computed tomography (CT) feature.

METHODS

Results of ocular examination, orbital CT examination and pathological findings in a patient with a space-occupying orbital lesion are presented.

RESULTS

Orbital CT evaluation of a male patient, aged one and a half years old, revealed a right orbital lesion with a strongly negative value in Hounsfield units. The preoperative diagnosis was a dermoid cyst. An anterior orbitotomy was performed, and the surgical specimen demonstrated a typical plexiform neurofibroma with routine hematoxylin and eosin staining and immunohistochemical studies.

CONCLUSIONS

Plexiform orbital neurofibromas may demonstrate a negative Hounsfield value on CT examination.

Orbital Decompression as an Alternative Management Strategy for Patients with Benign Tumors Located at the Orbital Apex

PURPOSE

Tumors located in the intraconal portion of the orbital apex, especially those inferior to the optic nerve, can be difficult to access surgically, carrying a significant risk of ocular morbidity. The purpose of this study was to investigate outcomes in 5 patients with benign-appearing but symptomatic tumors located in the intraconal portion of the orbital apex in which orbital decompression was performed as an alternative management strategy to resection.

DESIGN

Retrospective interventional case series.

PARTICIPANTS

Five patients were diagnosed with a compressive optic neuropathy secondary to a benign-appearing tumor at the orbital apex.

INTERVENTION

Each patient underwent surgical decompression of the affected orbit. None of the patients had the tumor biopsied or resected.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (VA), pupillary responses, visual fields (VFs), color vision, and orbital imaging.

RESULTS

Each of the patients demonstrated improvement in visual function, as measured by VA, VFs, and, in some cases, color vision. One patient required a second orbital decompression for recurrent optic neuropathy 4 years after the initial decompression. Complications included ptosis and enophthalmos in 2 patients and diplopia in the extreme right gaze in 1 patient.

CONCLUSIONS

Orbital decompression is a therapeutic option for patients with compressive optic neuropathies from benign orbital apex tumors, offering potential improvement in optic nerve function while sparing morbidity from attempts at surgical resection.

The optic nerve: radiologic, clinical, and pathologic evaluation

The radiologic investigation of the optic nerve plays an integral part in the diagnostic evaluation of diverse lesions of the optic pathways including inflammatory diseases, vascular disorders and benign and malignant tumors and these radiologic modalities consist principally of CT and MR imaging and, in vascular lesions, MR angiography and conventional angiography. The selection of radiologic studies and their focus is based on the ophthalmologic examination where the ophthalmologist can often determine the suspected location of lesions in the anterior or posterior visual pathways. Furthermore, inspection of the eye, including adnexal structures and funduscopy, provides additional information in the clinical assessment of these patients. With technical advances in the last few years, CT and MR imaging can detect lesions and determine their location and extent with high sensitivity and specificity. This article discusses the radiologic, clinical, and pathologic evaluation of the optic nerve.

Differentiation of cavernous hemangioma from schwannoma of the orbit: a dynamic MRI study

OBJECTIVE

The purpose of this study was to determine the capability of dynamic contrast MRI to differentiate hemangioma from schwannoma of the orbit.

MATERIALS AND METHODS

Sixteen patients (three males and 13 females; mean age, 39 +/- 17.3 [SD] years; age range, 10-71 years) with unilateral orbital tumors, including eight cavernous hemangiomas and eight schwannomas, were examined. In addition to conventional MRI, we performed a dynamic contrast study (fast spin-echo sequence, 20-sec interval) after bolus administration of the contrast material (gadopentetate dimeglumine, 0.1 mmol/kg). We evaluated the features of the contrast enhancement spread pattern and the tumors' time-intensity curves.

RESULTS

In the early phase, all the hemangiomas started the enhancement from one point or portion, although all the schwannomas started the enhancement from a wide area. The difference in the contrast-enhancement spread pattern features between the two types of tumors was statistically significant (p < 0.0001). The gradient of the time-intensity curve did not show a significant difference.

CONCLUSION

Hemangioma and schwannoma of the orbit can be differentiated by the contrast-enhancement spread pattern on dynamic MRI.

Orbital Schwannoma and Neurofibroma: Role of Imaging

Schwannomas are well-circumscribed ovoid masses that most commonly present in the superior orbit. Although it may be difficult to differentiate these benign masses from other orbital tumors on radiologic imaging, the CT and, in particular, the MR imaging characteristics can sometimes point to the diagnosis of a nerve sheath tumor. A definitive diagnosis can be made through correlation with histopathologic findings, however. In most cases, schwannomas have low malignant potential, and with total excision, recurrence is rare.

Imaging of orbital disorders in pediatric patients

The spectrum of orbital lesions occurring in childhood is wide, including a variety of both benign and malignant disorders. Although physical examination and fundoscopy may aid in establishing the diagnosis of retro-ocular lesions, imaging remains a critical step in the evaluation of the pediatric orbit. Ultrasonography, CT, and MR imaging are the primary modalities for the evaluation of the diseased orbit, and careful observation of the characteristic radiological features usually leads to correct diagnosis; however, some of the lesions look very similar and are difficult to differentiate from each other. The purpose of this article is to review the common and unusual entities that may involve the pediatric orbit, to describe the radiological features, and to evaluate the efficacy of US, CT, and MRI in the diagnosis and management of these conditions.

Localized neurofibroma of the orbit: a radiographic and histopathologic study

PURPOSE

To demonstrate the clinical, radiographic, intraoperative and histopathologic presentation of a localized neurofibroma of the orbit.

METHODS

Clinicopathologic case report.

RESULTS

A 25-year-old man was examined for inferior displacement of the right globe. Physical examination and neuro-imaging identified a localized solid tissue mass of the superior orbit. Histopathologic evaluation after complete surgical resection proved the lesion to be a localized neurofibroma.

CONCLUSIONS

The patient's history, clinical presentation, and imaging studies were strongly characteristic for this infrequently encountered orbital lesion. Several imaging features, including multilobulation, multiplicity, ring-configured contrast enhancement, and magnetic resonance imaging (MRI) signal intensity heterogeneity, when present in combination, may be reasonably diagnostic of this tumor.

The clinical spectrum of schwannomas presenting with visual dysfunction: a clinicopathologic study of three cases

Schwannomas (neurilemomas) are benign tumors that arise from Schwann cells in the peripheral nervous system. The most commonly involved nerves that cause neuro-ophthalmic manifestations are cranial nerves V and VIII. In this series of three women, schwannomas presented as intraconal masses that mimicked a cavernous hemangioma, a superior orbital mass transgressing the superior orbital fissure, and an expansive frontal lobe mass with clinical symptoms and signs of increased intracranial pressure. Although all three complained of visual blurring, none of our patients presented with Vth or VIIIth cranial nerve dysfunction. Histopathologic studies demonstrated well-circumscribed, encapsulated spindle-cell lesions with classic Antoni A and B patterns. Histopathologic examination is essential to confirm the diagnosis of a schwannoma that may be otherwise clinically confusing. Direct optic nerve compression, globe indentation with induced hyperopia, or increased intracranial pressure with optic nerve compromise may be responsible for visual symptoms. A multidisciplinary approach is often required because of the size and location of schwannomas.

Ophthalmoplegia and facial numbness following treated squamous carcinoma of the forehead

A 62-year-old man presented with progressive diplopia, left ptosis, proptosis, complete ophthalmoplegia, facial numbness, and headache of 2 1/2 months' duration. The symptoms started 1 month after surgical resection of a squamous cell carcinoma in the left side of the forehead. Imaging studies helped localize the lesion, correlating with clinical features. The differential diagnosis is discussed. The final diagnosis was confirmed by autopsy.

Neurilemmoma of the anterior ethmoidal nerve encroaching upon the nasolacrimal duct

The clinical, light microscopic, ultrastructural, and immunohistologic findings of a neurilemmoma encroaching upon the nasolacrimal duct are presented. This is the first reported case of this rare tumour of the nasolacrimal duct where the diagnosis has been confirmed by electron microscopy and immunohistochemical techniques.

Bilateral multiple cavernous haemangiomas of the orbit

Orbital cavernous haemangioma, a common orbital tumour, is usually single and unilateral. We report the first case of histologically confirmed bilateral multiple cavernous haemangiomas of the orbit.

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.

Orbital fibrous histiocytoma: computed tomography in 10 cases and a review of radiological findings

The computed tomographic features of 10 primary and secondary fibrous histiocytomas arising in the orbit are reviewed. Positive factors indicating the diagnosis were absent; orbital enlargement was more common in malignant tumours, but other indications of the degree of malignancy or invasiveness were present in only one case.

Do bilateral optic nerve sheath meningiomas exist?

All patients examined at The National Hospital for Nervous Diseases, Queen Square, from 1983 to 1987 with radiological evidence of meningiomas involving both optic nerves within the orbits have been reviewed. Their clinical and X-ray computed tomography (CT) features are different from those of patients with unilateral tumours, and they appear to form a separate group, probably representing optic nerve involvement by a primarily retro-orbital meningioma.