Orbital Schwannoma

Orbital schwannoma with hyposmia as the only presentation: Case report and a literature review on differential diagnosis

Orbital schwannoma is a rare benign tumor, originating from the Schwann cells of the orbital peripheral nerve sheath. Orbital schwannoma is easily misdiagnosed if the patient shows atypical presentations and atypical appearance on MRI imaging. A 56-year-old male experienced hyposmia for 1 year and was misdiagnosed with cavernous hemangioma pre-operation. This case was treated by surgery through the endoscopic trans-nasal approach. After operation, the patient had no recurrence or complications. Preoperative diagnosis for these cases remains difficult. Combined imaging modalities including computed tomography (CT) and magnetic resonance imaging (MRI) can help in differential diagnosis. Surgery is the main treatment modality for treating orbital schwannoma. Outcomes in most cases are favorable without complications or recurrence.

Conservative or surgical management of orbital schwannomas: a population-based case series

INTRODUCTION

Orbital schwannomas (OS) are rare occurrences with no more than 500 cases reported in the literature. The tumor's potential to compromise the delicate neuro-ophthalmic structures within the orbit prompts surgical removal. Tumor removal is performed by ophthalmologists, often requiring a multidisciplinary surgical approach. The literature contains a very limited number of cases managed non-surgically. However, the inherent risks of orbital surgery warrant a comparison of the outcomes of conservative and surgical management strategies.

AIMS

To review the national Swedish experience with the management of orbital schwannomas.

METHODS

The study center is the primary Swedish referral center for the multidisciplinary management of orbital tumors, including schwannomas. During the period of 2005 to 2021, 16 patients with an OS diagnosis were managed at the center.

RESULTS

Four patients initially underwent surgery where gross total resection (GTR) was achieved in three (75%) and subtotal resection (STR) in one (25%) case. The remaining 12 patients, who had a low risk of neuro-ophthalmic impairment, were managed conservatively with radiological and clinical examinations at regular intervals. After an average follow-up of 17 months, surgery was performed in three of these cases (25%). No recurrences or tumor growths were detected on radiological follow-ups (mean 50 months), and all patients experienced postoperative improvement at clinical follow-up (mean 65 months). The remainder of the conservatively treated patients (n=9) experienced no clinical progression (mean 30 months). A slight radiological tumor progression was detected in one patient after 17 months.

CONCLUSION

There were no differences in long-term outcome between patients who had been managed with early surgery and those operated later after an initially conservative management. Conservatively treated patients had minimal to no symptoms and remained clinically stable throughout the follow-up period. Based on these findings, conservative management may successfully be adopted in cases with mild symptoms, no signs of compressive optic neuropathy and low risk of neuro-ophthalmic impairment. Conversion to surgical management is indicated upon clinical deterioration or tumor growth. Based on the findings of this study a decision tree for the management of orbital schwannomas is suggested.

Extraocular Orbital and Peri-Orbital Masses

In this article, we will describe relevant anatomy and imaging findings of extraocular and orbital rim pathologic conditions. We will highlight important clinical and imaging pearls that help in differentiating these lesions from one another, and provide a few practical tips for challenging cases.

Orbital Schwannoma With Frontal Bone Lysis

Orbital schwannoma is an exceptionally rare cause of ptosis. Diagnosis may be elusive given its slow rate of growth and its various presentations depending on localization. Herein, we report the case of a 50-year-old male who presented to our clinic with a complaint of unilateral, recurrent ptosis of the left eye. He underwent levator palpebrae resection, which was unsuccessful at improving his ptosis. He later represented with acute-onset diplopia for which magnetic resonance imaging was obtained. Magnetic resonance imaging showed a lesion in the superior orbit with secondary bony dehiscence of the orbital roof. Through a vertical lid-split incision, the lesion was removed, and the frontal lobe was observed protruding through the defect in the orbital roof. This case highlights the importance of diagnostic skepticism in the face of recurrent ptosis and emphasizes the utility of the vertical lid-split approach for anterior lesions of the superior orbit.

Pediatric dumbbell-shaped orbital schwannoma with extension to the cranial cavity: A case report and literature review

Orbital schwannomas are rare in children, especially those with intracranial extension. Herein, our report refers to a 12-year-old boy who had a cranial-orbital mass with a dumbbell-like appearance. The total neoplasms was successfully removed via a transcranial approach, and the pathological diagnostic result was schwannoma. Neither radiotherapy nor chemotherapy was performed after surgery, and no recurrences were observed for 3 months. Our report suggests that orbital schwannomas should be differentiated from other types of orbital tumors with sufficient evidence and that complete surgical resection remains the first choice to cure this disease.

Bulbar conjunctival plexiform schwannoma in a 5-year-old patient; expect the unexpected!

Rare, atypical ophthalmological conditions in adults include bulbar conjunctival plexiform schwannomas, which are usually asymptomatic. Few case reports in the literature indicate the presence of orbital/conjunctival schwannomas in adult patients and, rarely, among children under the age of 12. We report a case of a 5-year-old girl who presented in an outpatient clinic with inferior temporal conjunctival nonpigmented cystic lesion of a 10 × 10 mm size. Upon examination, we could not identify a feeding vessel. The mass was mobile and not fixed to the sclera. The history indicated a 1-year duration but the mass in the left eye had progressively increased in size during the last 2 months prior to presentation. There was no traumatic injury or past history of ophthalmic surgery. Surgical excision of the cyst was sucessfully performed, and histopathological examination confirmed bulbar conjunctival plexiform schwannoma diagnosis. Upon regular follow-up evaluation, there was no evidence of recurrence or malignant transformation. Although it is extremely rare to encounter conjunctival schwannomas in children, it should be considered in ovoidal well-circumscribed orbital swellings, particularly those that appear with no history of trauma or surgery to the eye. Surgical excision is effective and safe therapeutic intervention.

Orbital Tumors-Clinical, Radiologic and Histopathologic Correlation

Orbital masses include a broad spectrum of benign and malignant entities. Often these masses are asymptomatic or show a slow growth rate, so that emergence of clinical symptoms is prolonged. In this context, cross-sectional imaging plays an elementary role in the characterization of these lesions. Aside from the characterization of the underlying entity, an evaluation of the involved compartments is possible by sufficient imaging, which also facilitates optimal treatment and surgery planning. The purpose of this review is to explore different benign and malignant orbital tumors and their typical appearance in imaging together with histopathologic findings.

MRI-Based Radiomics for Differentiating Orbital Cavernous Hemangioma and Orbital Schwannoma

Aim: The purpose of this work was to develop and evaluate magnetic resonance imaging (MRI)-based radiomics for differentiation of orbital cavernous hemangioma (OCH) and orbital schwannoma (OSC). Methods: Fifty-eight patients (40 OCH and 18 OSC, confirmed pathohistologically) screened out from 216 consecutive patients who presented between 2015 and 2020 were divided into a training group (28 OCH and 12 OSC) and a validation group (12 OCH and 6 OSC). Radiomics features were extracted from T1-weighted imaging (T1WI) and T2-weighted imaging (T2WI). T-tests, the least absolute shrinkage and selection operator (LASSO), and principal components analysis (PCA) were used to select features for use in the classification models. A logistic regression (LR) model, support vector machine (SVM) model, decision tree (DT) model, and random forest (RF) model were constructed to differentiate OCH from OSC. The models were evaluated according to their accuracy and the area under the receiver operator characteristic (ROC) curve (AUC). Results: Six features from T1WI, five features from T2WI, and eight features from combined T1WI and T2WI were finally selected for building the classification models. The models using T2WI features showed superior performance on the validation data than those using T1WI features, especially the LR model and SVM model, which showed accuracy of 93% (85-100%) and 92%, respectively, The SVM model showed high accuracy of 93% (91-96%) on the combined feature group with an AUC of 98% (97-99%). The DT and RF models did not perform as well as the SVM model. Conclusion: Radiomics analysis using an SVM model achieved an accuracy of 93% for distinguishing OCH and OSC, which may be helpful for clinical diagnosis.

Endoscopic Endonasal Removal of Orbital Schwannoma: Focus on Surgical Technique

Orbital schwannomas are a rare disease, representing about 1% of orbital tumors, potentially involving any subsite within the orbit. They usually present with painless, nonpulsatile proptosis, while diplopia and vision impairment due to extrinsic ocular muscles or optic nerve involvement are rarely observed.¹ A wait-and-see policy is advocated in case of small asymptomatic lesions. However, if progressive dimensional increase or symptoms are observed, surgical resection represents the treatment of choice.² Different surgical approaches have been proposed, mainly depending on tumor dimension and location inside the orbit, as well as surgical expertise. With advances in technology,³ knowledge,⁴ and surgical techniques,⁵ transnasal endoscopic approaches have emerged as a valid option in the management of lesions located medially to the optic nerve, with the advantage of improved visualization and overall decreased morbidity as compared with external approaches.⁶ We present the case of a 19-year-old woman, affected by an intraextraconal orbital schwannoma located in the left orbit's inferomedial aspect, with a 1-year history of left proptosis associated with retrobulbar pain exacerbated by the upward gaze. The lesion was completely removed with an endoscopic transnasal approach (Video 1), without evidence of postoperative sequelae or visual impairment. Magnetic resonance imaging performed 3 months after surgery showed good surgical results without evidence of persistence of disease. A multidisciplinary approach, involving different specialists familiar with orbital anatomy and physiology, is required for a proper management of patients affected by orbital pathologies.