Plexiform Schwannoma of the Eyelid.

Plexiform schwannoma of the lacrimal gland of the palpebral lobe has not been previously described. This 41-year-old male presented with a 2-year history of a left upper eyelid mass and associated regional irritation. MRI of the head and orbits confirmed a left superolateral multinodular mass centered on the palpebral lobe of the left lacrimal gland. Excision revealed a schwannoma of the plexiform subtype.

Magnetic Resonance Imaging of Idiopathic Orbital Myositis.

PURPOSE: To characterize the qualitative and quantitative features of idiopathic orbital myositis (IOM) on MRI. METHODS: This was a multicenter retrospective study of patients with active IOM with MRI. Patients with incomplete clinical records, poor-quality or interval scans without active myositis, and specific orbital myositis (i.e., orbital myositis secondary to an identified condition) were excluded. An enlargement ratio was calculated by dividing the diameters of the affected extraocular muscle (EOM) by the contralateral unaffected EOM. RESULTS: Twenty-four patients (mean age: 44.4 ± 17.8 years-old, male: 11) between 2011 and 2022 were included. One case (4.2%) was pediatric (17 years old), and 6 cases presented with recurrence. Active IOM was characterized by fusiform EOM enlargement, high T2 signal, and contrast enhancement. Average maximal EOM diameters ranged from 4.6 to 7.7 mm (enlargement ratio: 1.4-2.2). Eighteen (75%) patients had single EOM involvement, most commonly the medial rectus. Other ipsilateral structures affected included focal orbital fat (16/24, 66.7%) and lacrimal gland (8/24, 33.3%). Contralateral changes in the EOM and/or lacrimal gland were observed in 7 patients (29.2%). Patients presenting with recurrence were likely to develop ongoing recurrent episodes (p = 0.003). CONCLUSIONS: Various radiological patterns of involvement described including EOM enlargement, contrast enhancement, abnormal signal, and involvement of other orbital structures are indicative of active IOM. IOM remains a heterogeneous spectrum of acute and chronic clinico-radiological presentations. Inflammation may involve other ipsilateral or contralateral orbital structures or may be bilateral despite presenting clinically as unilateral disease. Quantitative measurements may have utility in differentiating IOM from other causes of orbital myositis.

A case of disseminated nocardiosis with orbital apex involvement and endophthalmitis.

Nocardia is a rare cause of ocular infections and most commonly occurs secondary to trauma. Systemic Nocardiosis may have ocular involvement in rare cases. We report a case of disseminated nocardiosis with orbital apex involvement and endophthalmitis in an immunocompromised patient. The patient presented with respiratory sepsis, and later developed complete ptosis and ophthalmoplegia in the left eye. This was on the background of treatment with high-dose prednisolone. Magnetic resonance imaging showed enhancement of the entire clivus, extending into the left orbital apex and cavernous sinus. The patient was initially treated empirically for CNS tuberculosis. Bronchoscopic cultures returned positive for Nocardia farcinica, and the patient was treated with trimethoprim/sulfamethoxazole and weaned off previous corticosteroids.

Primary orbital apocrine adenocarcinoma: case report and literature review.

Primary apocrine adenocarcinoma (PAA) originating from the orbit is a rare malignant neoplasm. We present the case of a 61-year-old-male with PAA of the orbit. The patient underwent a right orbital exenteration, neck dissection, and adjuvant radiotherapy. Orbital exenteration is commonly performed as the primary intervention for PAA of the orbit. The role of adjuvant radiotherapy to prevent local recurrence is unclear and may be determined on a case-by-case basis.

Extraocular muscle enlargement and proptosis in carotid cavernous fistulas.

PURPOSE: To evaluate the prevalence and pattern of extraocular muscle enlargement and proptosis in patients with carotid cavernous fistulas (CCF). METHODS: We conducted a retrospective study on patients with digital subtraction angiography (DSA) confirmed CCFs with neuroimaging (computed tomography or magnetic resonance imaging) performed prior to the DSA. The maximum extraocular muscle diameters were recorded. Extraocular muscles were considered enlarged if they were greater than two standard deviations above the normal muscle diameters. Proptosis was defined as the distance between the interzygomatic line to the anterior globe of ≥2 mm compared to the contralateral orbit or ≥21 mm. RESULTS: Forty orbits from 20 patients were included. The mean age of participants was 65 ± 15 years and 13 (65%) were female. Thirteen (65%) fistulas were indirect and seven (35%) were direct. There was enlargement of at least one muscle in 11 (27.5%) orbits, and this was not correlated with the type of fistula (direct/indirect). The inferior rectus was most commonly enlarged in seven orbits (17.5%), followed by the medial rectus in five orbits (12.5%). Proptosis was found in 17 (43%) orbits and was more common ipsilateral to the fistula (58% ipsilateral group vs 19% contralateral group, p < .01). CONCLUSION: Extraocular muscle enlargement was observed in over one-fourth of CCFs. When enlarged, the inferior and medial rectus muscles are most commonly involved. These findings may help clinicians and radiologists when evaluating the CT or MRI scans of patients with suspected CCFs.

Radiological differentiation between bacterial orbital cellulitis and invasive fungal sino-orbital infections.

PURPOSE: Invasive fungal orbital infections (IFOI) may be difficult to differentiate from sinogenic bacterial orbital cellulitis (OC). This study investigates the features differentiating OC from IFOI on magnetic resonance imaging (MRI). METHODS: Retrospective study of adult patients with sinogenic OC and IFOI with pre-intervention MRI. Patients without post-septal involvement, non-sinogenic OC (e.g.: secondary to trauma) and poor-quality scans were excluded. Independent Sample's t test and Fisher's exact test were conducted with p < 0.05 deemed statistically significant. RESULTS: Eleven cases each of OC (Mean age: 41.6 ± 18.4 years-old, Male: 10) and IFOI (Mean age: 65.0 ± 16.6 years-old, Male: 9) between 2006 and 2023. IFOI patients were older, more likely immunocompromised and had a lower mean white-cell count (p value = 0.005, 0.035 and 0.017, respectively). The ethmoid and maxillary sinuses were most commonly involved in both entities. Pre-septal and lacrimal gland involvement were more common in OC (p = 0.001 and 0.008, respectively). Infiltrative OC orbital lesions were poorly demarcated, whilst those in IFOI were expansile/mass-like invading the orbit from the adjacent paranasal sinuses. Specific IFOI features included loss-of-contrast-enhancement (LoCE) of paranasal sinus tissues with orbital extension. Extra-orbital and -sinonasal extension indicative of IFOI included contiguous skull base or pterygopalatine fossa involvement, retro-antral and masticator space stranding and vasculitis. CONCLUSION: This study describes the key MRI features of IFOI including differentiating markers from OC. These specific features, such as LoCE of the paranasal and orbital soft tissues, the location and pattern of contiguous soft-tissue involvement, provide expedient identification of IFOI which necessitate early surgical intervention for microbiological confirmation of an invasive fungal pathology.

Asymmetric proptosis in thyroid eye disease.

PURPOSE: Patients with thyroid eye disease (TED) can present with asymmetric disease. The purpose of this study was to evaluate the prevalence of asymmetric TED in an Australian cohort and investigate clinical, biochemical, and radiological associations of asymmetric TED. METHODS: This was a retrospective study of patients with TED who underwent Hertel exophthalmometry and orbital computed tomography (CT) scans. Asymmetry was defined as a difference in the globe protrusion of ≥ 3 mm using Hertel exophthalmometry. Data was collected on patient demographics, clinical disease presentation, thyroid function tests and antibody levels. Muscles volumes were determined by manually segmenting the extraocular muscles on CT scans using a commercially available software. RESULTS: 172 orbits from 86 patients were included in the study. 28 (33%) patients had asymmetric TED. No significant differences were observed in age, gender, thyroid hormone status, anti-thyroid peroxidase levels, thyroid stimulating hormone receptor antibodies, disease activity status, or dysthyroid optic neuropathy between the asymmetric and non-asymmetric groups. The extraocular muscle volumes were significantly higher in the asymmetric orbit compared to its contralateral orbit. CONCLUSION: Asymmetric TED is a reasonably common occurrence in the course of TED. It is associated with higher extraocular muscle volumes, suggesting muscle enlargement as one of the underlying contributors to asymmetric proptosis. Thyroid eye disease should be considered in the differential of asymmetric orbital inflammatory disease.

Evaluating the Ability of Open-Source Artificial Intelligence to Predict Accepting-Journal Impact Factor and Eigenfactor Score Using Academic Article Abstracts: Cross-sectional Machine Learning Analysis.

BACKGROUND: Strategies to improve the selection of appropriate target journals may reduce delays in disseminating research results. Machine learning is increasingly used in content-based recommender algorithms to guide journal submissions for academic articles. OBJECTIVE: We sought to evaluate the performance of open-source artificial intelligence to predict the impact factor or Eigenfactor score tertile using academic article abstracts. METHODS: PubMed-indexed articles published between 2016 and 2021 were identified with the Medical Subject Headings (MeSH) terms "ophthalmology," "radiology," and "neurology." Journals, titles, abstracts, author lists, and MeSH terms were collected. Journal impact factor and Eigenfactor scores were sourced from the 2020 Clarivate Journal Citation Report. The journals included in the study were allocated percentile ranks based on impact factor and Eigenfactor scores, compared with other journals that released publications in the same year. All abstracts were preprocessed, which included the removal of the abstract structure, and combined with titles, authors, and MeSH terms as a single input. The input data underwent preprocessing with the inbuilt ktrain Bidirectional Encoder Representations from Transformers (BERT) preprocessing library before analysis with BERT. Before use for logistic regression and XGBoost models, the input data underwent punctuation removal, negation detection, stemming, and conversion into a term frequency-inverse document frequency array. Following this preprocessing, data were randomly split into training and testing data sets with a 3:1 train:test ratio. Models were developed to predict whether a given article would be published in a first, second, or third tertile journal (0-33rd centile, 34th-66th centile, or 67th-100th centile), as ranked either by impact factor or Eigenfactor score. BERT, XGBoost, and logistic regression models were developed on the training data set before evaluation on the hold-out test data set. The primary outcome was overall classification accuracy for the best-performing model in the prediction of accepting journal impact factor tertile. RESULTS: There were 10,813 articles from 382 unique journals. The median impact factor and Eigenfactor score were 2.117 (IQR 1.102-2.622) and 0.00247 (IQR 0.00105-0.03), respectively. The BERT model achieved the highest impact factor tertile classification accuracy of 75.0%, followed by an accuracy of 71.6% for XGBoost and 65.4% for logistic regression. Similarly, BERT achieved the highest Eigenfactor score tertile classification accuracy of 73.6%, followed by an accuracy of 71.8% for XGBoost and 65.3% for logistic regression. CONCLUSIONS: Open-source artificial intelligence can predict the impact factor and Eigenfactor score of accepting peer-reviewed journals. Further studies are required to examine the effect on publication success and the time-to-publication of such recommender systems.

Orbital Artifacts on MRI.

PURPOSE: To describe artifacts on orbital MRI, which led to an incorrect radiology report. METHODS: Retrospective chart review of patients identified from the orbital databases at the Royal Adelaide Hospital and University of Wisconsin Hospital. Patients who had artifacts on orbital MRI that led to an incorrect radiology report were included. Records were evaluated for age at imaging, gender, MRI sequence, laterality, and location of artifact, radiological characteristics and misdiagnosis, and cause of artifact. RESULTS: Data were collected from 7 patients (3 male) who had a median age of 61 years at the time of imaging. Five artifacts resulted from fat-suppression failure with 4 of these cases misdiagnosed as inflammatory changes and 1 misdiagnosed as neoplastic infiltration. The OD was involved in 4 cases. Six cases were in the inferior orbit region. CONCLUSIONS: Fat-suppression failure artifacts may arise in the inferior orbit region and can be mistaken for inflammatory or neoplastic orbital disease. This may prompt additional investigations such as orbital biopsy. Clinicians should be aware of artifacts which can affect orbital MRI and lead to potential misdiagnosis.

Normative lacrimal gland dimensions by magnetic resonance imaging in an Australian cohort.

PURPOSE: To report the normative dimensions of the lacrimal gland on fat-suppressed contrast-enhanced magnetic resonance imaging (MRI) in an Australian cohort. METHODS: Retrospective review of patients who underwent 3 T orbital MRI is presented. Two hundred eleven orbits were used to conduct lacrimal gland measurements. Orbits were excluded if there was ipsilateral orbital or lacrimal gland disease, prior surgery, or poor image quality. The length and width of the lacrimal gland were measured in axial and coronal sections using the largest image. RESULTS: The mean lacrimal gland axial length was 14.6 mm in the right orbit and 14.3 mm in the left orbit. The mean axial width was 4.9 mm in both orbits. Coronal lengths averaged 16.2 mm in the right orbit and 16.4 mm in the left orbit. The coronal width averaged 4.8 mm in both orbits. A significant negative correlation was found between age and the right axial length (r = -0.26, p < .01) and the left axial length (r = -0.26, p < .01) of the lacrimal gland. No statistically significant difference was found between genders or laterality. CONCLUSION: This study presents the normal lacrimal gland dimensions on fat-suppressed contrast-enhanced MRI in an Australian cohort. An inverse relationship exists between age and the axial length of the lacrimal gland. These data may be used to help diagnose enlargement of the lacrimal gland.

Normative orbital measurements in an Australian cohort on computed tomography.

PURPOSE: To determine the normal diameters of the extraocular muscles (EOMs) and optic nerve sheath complex (ONSD) and correlate with patient demographics in an Australian cohort. METHODS: Consecutive patients who underwent contrast enhanced computed tomography (CT) orbits between December 2017 and March 2021 were included. Patients with bilateral disease, previous orbital surgery, or poor scan quality were excluded. Normal orbit was used in patients with unilateral orbital disease. RESULTS: Two hundred one orbits from 201 patients were included. Normal measurements (mean ± SD) were as follows: medial rectus (MR) 4.22 ± 0.56 mm; inferior rectus (IR) 4.20 ± 0.70 mm; lateral rectus (LR) 3.40 ± 0.56 mm; superior muscle group (SMG) 4.13 ± 0.72 mm; superior oblique (SO) 2.60 ± 0.43 mm; inferior oblique (IO) on quasi-sagittal plane 2.19 ± 0.42 mm, and the ONSD 5.62 ± 0.82 mm. The mean diameters of the LR, SMG, IR, SO, and ONSD were significantly larger in male than female patients (p < .05). Statistically significant correlation was found between age and the diameters of the LR (r = 0.29, p < .01), SMG (r = 0.22, p < .01), IO on a coronal plane (r = -0.18, p < .01), and ONSD (r = 0.16, p = .02). CONCLUSION: This normative data may be used to diagnose pathological enlargement of the optic nerve and extraocular muscles, including involvement of the oblique muscles.

Disseminated thrombosis of the internal jugular vein, superior ophthalmic vein and cavernous sinus as the primary manifestation of occult malignancy: a case report.

Internal jugular vein (IJV) thrombosis is a life-threatening condition most often associated with local risk factors such as head or neck infection or central venous catheterisation. Underlying malignancy is a rare but important aetiology to consider in patients presenting with spontaneous IJV thrombosis. We describe a case of necrotic cervical lymphadenopathy with thrombosis of the IJVs, cavernous sinuses and superior ophthalmic veins in a patient with metastatic squamous cell carcinoma, which was further complicated by an orbital compartment syndrome. The differential diagnosis of IJV thrombosis includes a range of infective, metastatic and thrombophilic pathologies. This case illustrates that, in the absence of an underlying precipitating factor, spontaneous IJV thrombosis should prompt further systemic investigations. Furthermore, patients with thrombotic events affecting the orbital venous drainage system should be monitored closely for signs of an acute orbital compartment syndrome.

Optic nerve infiltration in systemic non Hodgkin lymphoma.

Optic nerve infiltration secondary to systemic non-Hodgkin lymphoma (NHL) is a rare phenomenon. We present a 55-year-old man with low-grade systemic NHL who initially presented with an isolated optic neuropathy and non-specific neurological symptoms. We further present a literature review of systemic NHL with radiological evidence of optic nerve infiltration. On magnetic resonance imaging, the characteristic features include optic nerve enhancement and enlargement, while leptomeningeal enhancement is uncommon. Cerebrospinal fluid analysis and optic nerve sheath biopsy can return false negative results, and when such investigations are inconclusive, biopsy of the optic nerve substance has a high diagnostic yield. Although rare, lymphomatous optic nerve infiltration must be considered in the differential diagnosis of a pale swollen optic disc.

Cutaneous squamous cell carcinoma radiographically mimicking infiltration into the lacrimal gland.

Cutaneous squamous cell carcinoma (SCC) is a common malignancy of the skin, with the potential for local invasion and metastasis. Here, we present a case series of two patients with SCCs, suggesting radiological infiltration of the lacrimal gland on magnetic resonance imaging. However, histopathological examination revealed lymphoplasmacytic infiltration of the lacrimal gland consistent with dacryoadenitis, with no evidence of SCC infiltration. Our cases highlight the potential for peritumoural inflammation to cause dacryoadenitis and radiologically mimic tumour infiltration into the lacrimal gland.

Radiological analysis of orbital lymphoma histological subtypes.

PURPOSE: To characterise the radiological features of orbital lymphoma subtypes. METHODS: This was a multicentre, retrospective study to analyse radiological and clinical characteristics of orbital lymphoma by histological subtype across two sites within Australia and the United States. RESULTS: A total of eighty-eight patients were included. The most common subtypes were extranodal marginal zone lymphoma [EMZL] (48, 54.5%), follicular lymphoma [FL] (16, 18.2%), and diffuse large B-cell lymphoma [DLBCL] (15, 17.0%). Clinically, significant associations were found between DLBCL and vision change (p < .01), pain (p < .01), extraocular movement limitation (p = .01), and optic neuropathy (p = .01). Radiologically, there was no significant difference between the individual histopathological sub-groups with respect to bone destruction (p = .30), optic nerve involvement (p = .30) and diffuse appearance (p = .84). However, if categorised as either aggressive or indolent, aggressive lymphoma subtypes were significantly more likely to demonstrate globe indentation radiologically than indolent subtypes (Odds Ratio = 5.5, 95% CI: 1.3, 23.3; p = .02). CONCLUSIONS: DLBCL was significantly associated with vision change, pain, extraocular movement limitation and optic neuropathy clinically. Aggressive lymphoma subtypes were significantly more likely to demonstrate globe indentation radiologically. Otherwise, there were no significant differences between lymphoma subtypes and radiological findings on MRI and CT.

Dilated superior ophthalmic vein: systemic associations.

PURPOSE: To review systemic associations of patients with dilated superior ophthalmic veins (SOV) in the absence of orbital, cavernous sinus, or neurological disease. METHODS: Retrospective review of patients who had dilated SOVs with a diameter of ≥ 5.0 mm. Patients with a dilated SOV secondary to orbital, cavernous sinus or neurological disease were excluded. Patient demographics, past medical history, and SOV diameters on initial and follow up scans were collected. The maximum diameter of the SOV was taken perpendicular to the long axis of the SOV. RESULTS: Nine cases were identified. Patients ranged in age from 58 to 89 years and six out of nine were female. The dilated SOV involved both eyes in two cases, left eye in five cases and right eye in two cases. Three patients had dilated SOV likely secondary to raised venous pressures from decompensated right heart failure (n = 1), pericardial effusion (n = 1) and left ventricle dysfunction secondary to a myocardial infarction (n = 1). Five patients had a significant history of previous ischaemic heart or peripheral vascular disease. Two patients had risk factors for venous clotting disease whilst one patient had a history of giant cell arteritis and vertebral artery dissection. CONCLUSION: A dilated SOV may raise concern for life threatening conditions such as a carotid cavernous fistula and may prompt additional investigations. A dilated SOV may be reversible and secondary to raised venous pressures due to cardiac failure. Other cases may be seen in patients with significant cardiovascular risk factors, possibly due to changes in vasculature.

Orbital inflammation following COVID-19 vaccination: A case series and literature review.

PURPOSE: The purpose of the study was to report three cases of orbital inflammation following administration of the COVID-19 vaccination, manifesting as Tolosa-Hunt syndrome (THS) and orbital myositis. METHOD: A retrospective case series and literature review of patients who developed orbital inflammation following a COVID-19 vaccination. RESULTS: One patient presented with Tolosa-Hunt syndrome (THS) 14 days following her third (booster) COVID-19 vaccination, one patient developed orbital myositis 10 days following his first COVID-19 vaccination and one patient developed recurrent orbital myositis 1 and 7 days following her second and fourth COVID-19 vaccination. All patients received the Comirnaty vaccine (Pfizer-BioNTech). A thorough systemic autoimmune disease workup in both patients was unremarkable. Two patients had a prior history of orbital inflammation, with previous involvement of other different orbital structures. Characteristic MRI features for each pathology were observed, supporting the clinical presentation of THS and orbital myositis. There was complete resolution of THS following corticosteroids, with no recurrence at 2 months. Meanwhile, one case of orbital myositis self-resolved at 2 months without use of systemic corticosteroids, while the other patient with orbital myositis required treatment with intra-orbital steroid injections and oral corticosteroids. CONCLUSION: Orbital inflammation has been recognised as a rare adverse effect following COVID-19 vaccination. We present a case series of THS and orbital myositis as varied presentations of this entity.

Methicillin-resistant Staphylococcus aureus-associated orbital cellulitis: a case series.

PURPOSE: In recent years, methicillin-resistant Staphylococcus aureus (MRSA) orbital cellulitis (OC) has drawn increasing clinical and public health concern. We present a case series of MRSA OC encountered at four Australian tertiary institutions. METHODS: A multi-centre retrospective case series investigating MRSA OC in Australia from 2013 to 2022. Patients of all ages were included. RESULTS: Nine cases of culture-positive non-multi-resistant MRSA (nmMRSA) OC were identified at four tertiary institutions across Australia (7 male, 2 female). Mean age was 17.1 ± 16.7 years (range 13-days to 53-years), of which one was 13 days old, and all were immunocompetent. Eight (88.9%) patients had paranasal sinus disease, and seven (77.8%) had a subperiosteal abscess. Four (44.4%) had intracranial extension, including one (11.1%) case which was also complicated by superior sagittal sinus thrombosis. Empirical antibiotics, such as intravenous (IV) cefotaxime alone or IV ceftriaxone and flucloxacillin, were commenced. Following identification of nmMRSA, targeted therapy consisting of vancomycin and/or clindamycin was added. Nine (100%) patients underwent surgical intervention. Average hospital admission was 13.7 ± 6.9 days (range 3-25 days), with two patients requiring intensive care unit (ICU) admission due to complications related to their orbital infection. All patients had favourable prognosis, with preserved visual acuity and extraocular movements, following an average follow-up period of 4.6 months (range 2-9 months). CONCLUSION: NMMRSA OC can follow an aggressive clinical course causing severe orbital and intracranial complications across a wide demographic. However, early recognition, initiation of targeted antibiotics and surgical intervention when required can effectively manage these complications and achieve favourable visual outcomes.

Extraocular muscle enlargement.

Extraocular muscle enlargement can occur secondary to a range of orbital and systemic diseases. Although the most common cause of extraocular muscle enlargement is thyroid eye disease, a range of other inflammatory, infective, neoplastic, and vascular conditions can alter the size and shape of the extraocular muscles. Imaging with computed tomography and magnetic resonance imaging plays an essential role in the workup of these conditions. This article provides an image-rich review of the wide range of pathology that can cause enlargement of the extraocular muscles.

Diagnostic Utility of Diffusion-Weighted Imaging and Apparent Diffusion Coefficient for Common Orbital Lesions: A Review.

PURPOSE: To review and summarize the existing literature surrounding the clinical use of diffusion-weighted imaging and apparent diffusion coefficient (ADC) as diagnostic tools in differentiating common orbital lesions. METHODS: A systematic literature review on the use of ADC and diffusion-weighted imaging sequences for orbital imaging was performed. Only original research articles that reported ADC values for benign or malignant lesions were included. RESULTS: Malignant orbital tumors have an overall lower mean ADC value than benign masses. Orbital lymphoma is characterized by consistently lower ADC values compared with other malignant orbital masses; a threshold value less than 0.775 × 10 -3 mm 2 /s has been proposed to distinguish orbital lymphoma from other neoplastic and non-neoplastic orbital masses. To differentiate orbital inflammatory disease from lymphoma, an ADC threshold greater than 0.92 × 10 -3 mm 2 /s has been proposed. CONCLUSIONS: Orbital masses encompass a host of benign and malignant etiologies and can present a diagnostic challenge on both clinical and radiological assessment. Recent advanced MRI techniques such as diffusion-weighted imaging and ADC can improve the diagnostic specificity for orbital disease, particularly in differentiating benign from malignant lesions and lymphoma from orbital inflammatory disease.