Orbital Myositis: A Comprehensive Review and Reclassification

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.

Neuromuscular junction disorders: mimics and chameleons

Neuromuscular junction (NMJ) disorders represent a heterogenous group of acquired and congenital disorders that present in variable and distinctive ways. The diagnosis is typically reached through a combination of clinical, serological, pharmacological and electrophysiological evaluation. While the diagnosis can be fairly straightforward in some cases, the overlap with other neurological disorders can make diagnosis challenging, particularly in pure ocular presentations and in seronegative patients. The over-reliance on serological tests and electrophysiological evaluation in isolation can lead to misdiagnosis. In this article, we provide an overview of the NMJ disorders, discuss red flags for the key differential diagnoses (mimics) and report the atypical ways in which NMJ disorders may present (chameleons).

An Evidence-Based Approach to Diagnosing Patients Presenting With Orbital Inflammatory Syndromes (An American Ophthalmological Society Thesis)

PURPOSE

The initial management of patients presenting with orbital inflammatory syndromes varies-with some pursuing a diagnostic workup while others treat without any testing. The evidence behind this rationale is limited. A review of patients with orbital inflammation is performed with an analysis of diagnostic testing to develop a workflow for such patients.

DESIGN

A retrospective review of patients presenting with acute orbital inflammation at a single institution from 2011 to 2020 was conducted.

METHODS

Orbital imaging was required for inclusion. Patients with high suspicion of neoplasm, bacterial infection, vascular malformation, or thyroid eye disease were excluded. A review of presenting clinical findings, laboratory workup, orbital imaging, and biopsy were performed. Statistical analysis was performed identifying statistically significant diagnostic and treatment maneuvers.

RESULTS

In total, 172 patients met inclusion criteria (66% female, mean age 46 years). The primary clinical presentation was myositis, dacryoadenitis, and infiltrative in 67, 73, and 32 patients (39.0%, 43.0%, 18.6%, respectively). Laboratory studies were conducted in 145 (84%) while biopsy was performed in 55 (32%). Specific orbital inflammation (SOI) was diagnosed in 29 (16.9%) with the most frequent diagnoses being sarcoidosis, IgG4-related disease, inflammatory bowel disease, and systemic lupus erythematosus. The majority (147, 85.5%) was initially treated with steroids, but steroid-sparing agent use was statistically higher in patients with SOI.

CONCLUSIONS

In patients presenting with orbital inflammatory syndromes, distinguishing myositis, dacryoadenitis, and infiltrative disease has workup and differential diagnosis impacts. Because SOI is relatively common, sequelae of SOI, and potential steroid-sparing therapy needs, diagnosis via an evidence-based systemic approach is critical. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

[Interdisciplinary Management of Orbital Diseases]

Diagnosis and therapy of orbital diseases is an interdisciplinary challenge, in which i.e. otorhinolaryngologists, ophthalmologists, radiologists, radiation therapists, maxillo-facial surgeons, endocrinologists, and pediatricians are involved. This review article describes frequent diseases which both, otolaryngologists and ophthalmologists are concerned with in interdisciplinary settings. In particular the inflammatory diseases of the orbit including orbital complications, autoimmunological diseases of the orbit including Grave´s orbitopathy, and primary and secondary tumors of the orbit are discussed. Beside describing the clinical characteristics and diagnostic steps the article focusses on the interdisciplinary therapy. The review is completed by the presentation of most important surgical approaches to the orbit, their indications and possible complications. The authors tried to highlight the relevant facts despite the shortness of the text.

Ocular motor and vestibular dysfunction in central nervous system lymphoma

BACKGROUND AND PURPOSE

Diagnosis of lymphoma involving the central nervous system (CNS) is challenging. This study aimed to explore the abnormal vestibular and ocular motor findings in CNS lymphoma.

METHODS

A retrospective search of the medical records identified 30 patients with CNS lymphoma presenting ocular motor and vestibular abnormalities from four neurology clinics of university hospitals in South Korea (22 men, age range 14-81 years, mean 60.6 ± 15.2). The demographic and clinical features and the results of laboratory, radiological and pathological evaluation were analyzed.

RESULTS

Patients presented with diplopia (13/30, 43%), vestibular symptoms (15/30, 50%) or both (2/30, 7%). In 15 patients with diplopia, abnormal ocular motor findings included ocular motor nerve palsy (n = 10, 67%), internuclear ophthalmoplegia (n = 2, 13%), external ophthalmoplegia (n = 2, 13%) and exophoria (n = 1, 7%). The vestibular abnormalities were isolated in 14 (82%) of 17 patients with vestibular symptoms and included combined unilateral peripheral and central vestibulopathy in three from lesions involving the vestibular nuclei. CNS lymphoma involved the brainstem (53%), cerebellum (33%), leptomeninges (30%), deep gray nuclei (23%) or cranial nerves (17%). Two patients showed the "double-panda" sign by involving the midbrain.

CONCLUSIONS

This study expands the clinical and radiological spectra of CNS lymphoma. Neuro-ophthalmological and neuro-otological evaluation may guide the early diagnosis of CNS lymphoma.

A Case of Idiopathic Orbital Inflammation With Elevated Anti-Mumps Immunoglobulin M Antibody

A 21-year-old female presented with periocular swelling, diplopia, and painful ophthalmoplegia in the OS. Orbital magnetic resonance imaging revealed an enhanced soft tissue mass involving the left medial rectus muscle. Laboratory test results revealed leukocytosis, elevated reactive C-reactive protein, and positive serum levels of anti-mumps immunoglobulin M (IgM) antibody without systemic manifestations of mumps infection. The clinical course was refractory, and the patient showed a poor response to high-dose steroids. An incisional biopsy revealed stromal fibrosis with focal lymphoid aggregates, indicating sclerosing inflammation. Myopathy of the medial rectus progressed to superior, inferior, and lateral recti involvement of the left orbit. Immunosuppressive agents, including steroids, were administered for 22 months after disease onset. The mumps IgM antibody level was positive for over 5 months and became negative upon testing performed 1 year after the first visit.

Recurrent inferior oblique myositis and its outcomes

This report presents a unique case of recurrent idiopathic inferior oblique myositis (IOM) with a focus on clinico-radiological characteristics and histological features. A woman in her early 40s presented with a third episode of IOM following a 12-year period of quiescence. The first two episodes were characterised by unilateral IOM with rapid resolution following oral prednisone treatment. MRI revealed anterior focal enlargement of the left inferior oblique muscle with ipsilateral lacrimal gland enlargement. An inferior oblique muscle and lacrimal gland biopsy demonstrated significant inflammatory infiltrate. An intraorbital injection of triamcinolone acetonide was administered with complete resolution of symptoms within 1 week.

Paraneoplastic orbital myositis as a first manifestation of renal cell carcinoma

Paraneoplastic syndromes (PNSs) are remote effects of the primary tumor on tissues and organs, not related to direct invasion or metastasis. Ophthalmological involvement has been reported in 0.01-0.1% cases of PNSs. It may present as retinopathy, optic neuritis, myasthenia-like syndromes, or orbital myositis (OM), among others. An 89-year-old male with bilateral ocular pain and chemosis, was given an initial diagnosis of bilateral acute conjunctivitis. After 5 days, the patient presented worsening of the pain and bilateral complete ophthalmoplegia. Cranial CT scan showed diffuse bilateral thickening of the four rectus muscles. Inflammatory markers, thyroid hormones, and thyroid antibodies were normal. An abdominal ultrasound test was performed, observing a mass in the right kidney. After confirmation of the lesion with a CT scan, the radiological characteristics of the lesion were highly suggestive of renal cell carcinoma. Treatment with intravenous corticosteroids was ensued with complete resolution of all ophthalmological symptoms. Paraneoplastic orbital panmyositis was first described in 1994. Since then it has been reported scarcely, remaining an extremely rare entity. To our knowledge, this is the first report of its association with renal cell carcinoma. In the absence of inflammatory or dysthyroid blood markers, bilateral orbital panmyositis warrants further investigation for a possible underlying oncological pathology.

Orbital myositis and scleritis after anti-SARS-CoV-2 mRNA vaccines: A report of three cases

PURPOSE

To report three cases of ocular myositis and scleritis, bilateral scleritis and unilateral single muscle myositis after mRNA COVID-19 vaccination.

METHODS

Case series of three patients who presented to the Orbit Outpatient Service of Fondazione Policlinico Universitario A. Gemelli with a history of unilateral proptosis, diplopia and pain, bilateral red eye and pain during eye movements and unilateral proptosis and inconstant diplopia respectively with onset 5-10 days after m-RNA COVID-19 vaccine. A thorough hematologic work up and orbital contrast enhanced magnetic resonance imaging (MRI) in patients with proptosis was performed.

RESULTS

Patients were females, 64, 58 and 45 years old respectively. MRI showed enlargement of all right rectus muscles, with both muscle belly and insertion involvement in the first case associated to right scleritis. A bilateral scleritis was diagnosed in the second patient and a single muscle myositis in the third patient. Serological tests excluded thyroid diseases. The first and second patient were treated respectively with oral and topical glucorticoids with a complete clinical response. Two 2 cycles of oral non-steroidal anti-inflammatory drugs were administered to the third patient with a partial response.

CONCLUSION

As far as we know these are the first report of orbital myositis and scleritis presenting after mRNA BNT162b2 vaccine (Pfizer/BioNTech) and mRNA-1273-(Moderna) vaccine, an uncommon effect of a likely autoimmune reaction triggered by the virus antigen.

Proptosis secondary to bilateral extraocular muscle enlargement in Noonan syndrome with hypertrophic cardiomyopathy: A case report

PURPOSE

To report and investigate proptosis in a young girl with Noonan syndrome.

METHODS

Observational case report.

RESULTS

A 16-year-old girl affected by Noonan syndrome underwent a complete ophthalmological examination showing bilateral proptosis with hypofunction of lateral rectus and superior oblique muscles. Visual acuity, color discrimination and fundus examination were unremarkable. The orbital MRI showed bilateral proptosis and symmetrical enlargement of extraocular muscles, with bellies thickening and tendon sparing. The young patient also complained restrictive hypertrophic cardiomyopathy.

CONCLUSIONS

Proptosis is an uncommon ocular manifestation of Noonan syndrome and its pathophysiology has never been clarified. The MRI evidence of extraocular muscles enlargement associated with hypertrophic cardiomyopathy, led us to hypothesize a common altered pathway beneath these features, more specifically the MAP kinase pathway, since extraocular and cardiac muscles share a mesenchymal embryological origin.

Varicella zoster virus meningoencephalitis presenting as orbital myositis - a case report

The authors present a case of meningoencephalitis caused by Varicella zoster virus (VZV) infection, which initially manifested as orbital myositis followed by rapid progression to orbital apex syndrome, meningoencephalitis and death. There was no development of a cutaneous rash. An orbital biopsy demonstrated VZV infection, which was confirmed on a lumbar puncture. In this case, VZV meningoencephalitis was not responsive to steroid or antiviral therapy. This case highlights an atypical presentation of VZV with orbital myositis preceding intracranial involvement.

Characterization of patients with ocular pain evaluated with ultrasound

BACKGROUND

The cause of ocular pain in the quiet eye is challenging to diagnose. It is a common complaint in the ophthalmology clinic and there are no actual guidelines on the exams that should be ordered initially. We decided to characterize patients with eye pain and normal ophthalmological examination who underwent ocular ultrasound, their findings, and systemic work-up.

METHODS

A retrospective chart review of patients who underwent ocular ultrasound due to ocular pain and no clinical findings on initial slit-lamp examination. We evaluated patient characteristics and analyzed systemic work-up results in contrast to ocular ultrasound findings.

RESULTS

Two hundred and three patients with normal slit-lamp examination and ocular pain were evaluated using ocular ultrasound at Clinica Barraquer. Most of the patients were women (88.7%), and 55% were older than 50 years. Nearly all of the patients had echographic findings, 87.7% of patients showed evidence of scleral scars, from which 66.5% had signs of activity, and 42.9% had thickened extraocular muscles. In general, most patients with ocular pain had normal results on systemic work-up, but the patients who did have positive results tended to have echographic findings.

CONCLUSION

Posterior inflammation is present in most patients with ocular pain in a quiet eye, and echography is an optimal tool to identify this. There is a tendency towards abnormal autoimmune test results and echographic findings. This should be considered in the initial work-up of these patients, given the importance of early diagnosis and the threat of vision loss with severe inflammation.

Idiopathic orbital myositis in a pregnant woman

A case of a 29-year-old woman who presented at 25 weeks' gestation with acute onset of painful diplopia and periorbital swelling is presented. Following further investigation, a diagnosis of idiopathic acute lateral rectus myositis was established. Her condition resolved following a 4-week course of oral prednisolone without recurrence. A healthy female was delivered at 40 weeks' gestation. The presenting features, differential diagnosis, treatment and course of orbital myositis are discussed.

Clinical and imaging clues to the diagnosis and follow-up of ptosis and ophthalmoparesis

Ophthalmoparesis and ptosis can be caused by a wide range of rare or more prevalent diseases, several of which can be successfully treated. In this review, we provide clues to aid in the diagnosis of these diseases, based on the clinical symptoms, the involvement pattern and imaging features of extra-ocular muscles (EOM). Dysfunction of EOM including the levator palpebrae can be due to muscle weakness, anatomical restrictions or pathology affecting the innervation. A comprehensive literature review was performed to find clinical and imaging clues for the diagnosis and follow-up of ptosis and ophthalmoparesis. We used five patterns as a framework for differential diagnostic reasoning and for pattern recognition in symptomatology, EOM involvement and imaging results of individual patients. The five patterns were characterized by the presence of combination of ptosis, ophthalmoparesis, diplopia, pain, proptosis, nystagmus, extra-orbital symptoms, symmetry or fluctuations in symptoms. Each pattern was linked to anatomical locations and either hereditary or acquired diseases. Hereditary muscle diseases often lead to ophthalmoparesis without diplopia as a predominant feature, while in acquired eye muscle diseases ophthalmoparesis is often asymmetrical and can be accompanied by proptosis and pain. Fluctuation is a hallmark of an acquired synaptic disease like myasthenia gravis. Nystagmus is indicative of a central nervous system lesion. Second, specific EOM involvement patterns can also provide valuable diagnostic clues. In hereditary muscle diseases like chronic progressive external ophthalmoplegia (CPEO) and oculo-pharyngeal muscular dystrophy (OPMD) the superior rectus is often involved. In neuropathic disease, the pattern of involvement of the EOM can be linked to specific cranial nerves. In myasthenia gravis this pattern is variable within patients over time. Lastly, orbital imaging can aid in the diagnosis. Fat replacement of the EOM is commonly observed in hereditary myopathic diseases, such as CPEO. In contrast, inflammation and volume increases are often observed in acquired muscle diseases such as Graves' orbitopathy. In diseases with ophthalmoparesis and ptosis specific patterns of clinical symptoms, the EOM involvement pattern and orbital imaging provide valuable information for diagnosis and could prove valuable in the follow-up of disease progression and the understanding of disease pathophysiology.

MRI in the assessment of thyroid-associated orbitopathy activity

Management of patients with thyroid-associated orbitopathy (also called Graves' disease) is dependent on the assessment of the disease activity. Evaluation of disease activity is based on ophthalmological examination. Magnetic resonance imaging (MRI) is an auxiliary method that may help quantify the activity and is also helpful in obtaining anatomical information concerning muscle thickness, exophthalmos, or optic neuropathy. We present a review of MRI techniques of the orbits with emphasis on the evaluation of disease activity. The most convincing seems to be the group of T2-weighted techniques such as conventional T2 weighting, T2 relaxometry, and T2 mapping. Dynamic contrast-enhanced MRI is another promising method.

Evaluation of Orbital Lymphoproliferative and Inflammatory Disorders by Gene Expression Analysis

Non-specific orbital inflammation (NSOI) and IgG4-related orbital disease (IgG4-ROD) are often challenging to differentiate. Furthermore, it is still uncertain how chronic inflammation, such as IgG4-ROD, can lead to mucosa-associated lymphoid tissue (MALT) lymphoma. Therefore, we aimed to evaluate the diagnostic value of gene expression analysis to differentiate orbital autoimmune diseases and elucidate genetic overlaps. First, we established a database of NSOI, relapsing NSOI, IgG4-ROD and MALT lymphoma patients of our orbital center (2000−2019). In a consensus process, three typical patients of the above mentioned three groups (mean age 56.4 ± 17 years) at similar locations were selected. Afterwards, RNA was isolated using the RNeasy FFPE kit (Qiagen) from archived paraffin-embedded tissues. The RNA of these 12 patients were then subjected to gene expression analysis (NanoString nCounter®), including a total of 1364 target genes. The most significantly upregulated and downregulated genes were used for a machine learning algorithm to distinguish entities. This was possible with a high probability (p < 0.0001). Interestingly, gene expression patterns showed a characteristic overlap of lymphoma with IgG4-ROD and NSOI. In contrast, IgG4-ROD shared only altered expression of one gene regarding NSOI. To validate our potential biomarker genes, we isolated the RNA of a further 48 patients (24 NSOI, 11 IgG4-ROD, 13 lymphoma patients). Then, gene expression pattern analysis of the 35 identified target genes was performed using a custom-designed CodeSet to assess the prediction accuracy of the multi-parameter scoring algorithms. They showed high accuracy and good performance (AUC ROC: IgG4-ROD 0.81, MALT 0.82, NSOI 0.67). To conclude, genetic expression analysis has the potential for faster and more secure differentiation between NSOI and IgG4-ROD. MALT-lymphoma and IgG4-ROD showed more genetic similarities, which points towards progression to lymphoma.

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.

Clinical heterogeneity between two subgroups of patients with idiopathic orbital inflammation

Objective

Idiopathic orbital inflammation (IOI) is a group of orbital inflammatory diseases of unknown etiopathogenesis. We investigated whether patients with IOI have clinical heterogeneity based on the presence (typical group) or absence (atypical group) of a unique onset that periocular inflammatory symptoms emerge suddenly but progress slowly.

Methods and analysis

This retrospective cohort study included 195 patients diagnosed with IOI. We analysed the clinical data of patients, including the outcomes of corticosteroid treatment, in two subgroups stratified on the basis of the presence (130 patients) or absence (65 patients) of the unique onset.

Results

Patients in the typical group were significantly younger at disease onset than those in the atypical group (median age; 52 vs 65 years, p=0.002); had more ocular adnexa-specific lesions, namely, dacryoadenitis, myositis, scleritis and optic perineuritis (78% vs 45%, p=0.00001); and had significantly fewer associations with immune-mediated inflammatory diseases (4% vs 15%, p=0.004). Among 30/119 patients (25%) who were steroid refractory in the typical group, a long period of time from symptom onset to initiation of treatment was a significant steroid-refractory risk factor (OR: 16.7), whereas, among the 18/40 patients (45%) who were steroid refractory in the atypical group, intraconal diffuse lesions were a significant steroid-refractory risk factor (OR: 8.8).

Conclusion

This cohort study suggests clinical heterogeneity between the two subgroups of patients with IOI.

Bilateral Paraneoplastic Orbital Myositis Associated With Malignant Melanoma and Multiple Myeloma

Paraneoplastic extraocular muscle enlargement has been reported in a small number of patients with cancers including breast or lymphoma, usually presenting with bilateral multiple muscle involvement. Such myositis may be autoimmune. Furthermore, orbital inflammation is a recognized complication of immune-modulation therapy used to treat melanoma, such as ipilimumab. Extraorbital myositis has been described in myeloma, and polymyositis in melanoma. We present a case of bilateral, asymmetrical extraocular muscle enlargement with spontaneous resolution in a patient with simultaneous new diagnoses of metastatic malignant melanoma and multiple myeloma. A similar episode 7 months before diagnosis also resolved spontaneously. The authors believe this to be the first reported case of paraneoplastic orbital myositis associated with multiple myeloma or untreated malignant melanoma.

Orbital myositis in systemic lupus erythematosus: a case-based review

Ocular complications occur in up to one-third of patients with systemic lupus erythematosus (SLE). Among them, orbital myositis (OM) is considered a rare manifestation that affects the extraocular muscles and causes pain and restriction with eye movement. We report a case of OM in a 48-year-old female with SLE and secondary Sjogren's Syndrome, who presented headache, periorbital edema, and painful ocular movements in both eyes, with no other systemic manifestations. An orbital magnetic resonance image revealed thickening of the right medial rectus and left lateral rectus muscles. Laboratory tests were normal and there was no further disease activity. The patient was treated with prednisone 1 mg/Kg/day with a resolution of symptoms. We found 13 additional cases of OM from our literature review (11 SLE patients and 2 with discoid lupus erythematosus). There was a female predominance in these cases with a mean age of 43.6 years (SD ± 16.9). Their main clinical features included eye pain, swelling, proptosis, diplopia, and limitations in extraocular muscles, while in most of them, there was no other active systemic manifestation. Treatment with steroids led to the complete resolution of symptoms in most of these patients. The available evidence suggests that it is essential to have a high index of suspicion for OM in SLE patients even when there is no systemic disease activity so that proper treatment is initiated early.

Etiology and Clinical Features of Diplopia in South China: Analysis of 303 Cases

Purpose

To provide a new classification system for diplopia and evaluate the etiology and clinical features of diplopia subtypes in south China.

Methods

In this retrospective study, all patients presenting with diplopia over the period from 2012 to 2014 in south China were reviewed. Patients were categorized into 3 groups according to their extraocular muscle (EOM) dysfunction: single EOM (sEOM), multiple EOMs (mEOMs), and a comitant strabismus group. Clinical data evaluated included age, sex, medical history, etiology and duration of diplopia, ocular alignment, and ocular motility.

Results

A total of 303 patients were enrolled. The most common type of EOM dysfunction was sEOM (158 cases, 52.1%), followed by mEOMs (n = 119, 39.3%), and finally the comitant strabismus group (n = 26, 8.6%). Overall, the most common cause of diplopia involved orbital diseases. Within the sEOM group, microangiopathy (n = 42, 26.6%) and trauma (n = 41, 25.9%) were the major etiologies, with the lateral rectus (LR) (n = 86, 54.4%) being the most frequently involved. There were 12 (4.0%) patients who were considered as nasopharyngeal carcinoma (NPC)-associated diplopia (10 caused by radiation neuropathy following radiation therapy). Thyroid associated ophthalmopathy (TAO, 56 cases, 47.1%) was the predominant etiology found in the mEOMs group. Acute acquired comitant esotropia (AACE, 14 cases, 53.9%) was the most common etiology in the comitant strabismus group.

Conclusions

This new classification system for assessing diplopia as based on EOM dysfunction represents an easy-to-follow approach that can be readily adapted for the clinical use. While microangiopathy and trauma represent common etiologies of diplopia, both orbital diseases and NPC-associated diplopia also warrant special attention when assessing diplopia within patients in south China.

Idiopathic Orbital Myositis Revisited

PURPOSE OF REVIEW

To review current knowledge regarding idiopathic orbital myositis.

RECENT FINDINGS

Recent publications have focused on possible causes of orbital myositis and the process to reach a diagnosis of idiopathic orbital myositis. With inflamed and enlarged extraocular muscles, features to distinguish between competing diagnostic possibilities are based on imaging in the context of history and clinical signs. Idiopathic orbital myositis is characterized by the clinical triad of acute onset of orbital pain exacerbated on eye movement, double vision, and redness or swelling of the eyelids or conjunctiva, along with the radiological finding of homogeneous, fusiform enlargement of one or more extraocular muscles. In atypical or inconclusive clinico-radiological findings for a diagnosis of idiopathic orbital myositis, or where the clinical behavior changes or fails to respond to corticosteroid treatment, a systemic and oncologic work-up and muscle biopsy are warranted to exclude specific local or systemic disease as cause of the inflamed and enlarged muscle. As our understanding of idiopathic orbital myositis evolves, the diagnostic focus is shifting toward earlier identification of underlying local or systemic disease through systemic work-up and muscle biopsy.

Orbital Muscle Enlargement: What if It’s Not Graves’ Disease?

Purpose of Review

To provide the radiologist with tools to recognize findings atypical for Graves’ ophthalmopathy and differentiate between the most important and common alternative causes of extraocular muscle enlargement on CT and MR imaging.

Recent findings

We introduce five ‘red flags’ representing features that are atypical for Graves’ ophthalmopathy: unilateral disease, atypical pattern of muscle involvement, adjacent structure involvement, restricted diffusion, and absence of pain.

Summary

About 95% of the cases with extraocular enlargement are due to Graves’ ophthalmopathy, other causes are less well known and recognized. The ‘red flags’ may aid in recognizing and suggesting alternative diagnoses.

Orbital inflammatory disease associated with COVID-19 infection

Conjunctival congestion has been reported as the most common ophthalmic manifestation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, affecting 18.4%-31.6% of patients with corona virus disease 2019 (COVID-19). Orbital inflammatory disease has been rarely reported in association with COVID-19 infection, with only 2 case reports of adolescent patients having been recently published. We present a unique case of orbital myositis in a 10-year-old boy who tested positive for SARS-CoV-2 infection in the absence of typical systemic COVID-19 manifestations. Although it is uncertain whether SARS-CoV-2 infection triggered the inflammation or was coincidental, the possible association of the events is concerning.

[Idiopathic orbital inflammation]

BACKGROUND

Orbital inflammatory disease encompasses a spectrum of disorders. Idiopathic orbital inflammation (IOI) is often a diagnosis of exclusion, which needs to be differentiated from infections, systemic inflammatory disease, and neoplasms. IOI includes anterior inflammation with dacryoadenitis, myositis, perineuritis of the optic nerve, periscleritis, diffuse sclerosing inflammation, and orbital apex inflammation.

OBJECTIVE

A differential diagnostic overview of IOI is presented, including its subcategories, diagnosis, and treatment.

CONCLUSION

The diagnosis of IOI is often made by exclusion with typical clinical findings, CT and MRI scans, and pathology. Treatment includes corticosteroids, immunomodulators, immunosuppressants, and radiotherapy.

Myositis of an Extraocular Muscle, a Possible Drug Reaction: Histopathologic and Immunopathologic Analysis

A 58-year-old man presented with left-sided orbital inflammation, including chemosis and a lateral rectus abduction defect. Initially presumed to represent cellulitis, the condition responded poorly to oral and intravenous antibiotics. CT showed the epicenter of an infiltrate to involve the lateral rectus. The patient improved dramatically when oral prednisone was added. Lateral rectus biopsy displayed intramuscular polyclonal lymphoid infiltrates, rich with eosinophils. Complete resolution of the inflammatory process was confirmed by a follow-up CT. The presumptive diagnosis was idiopathic orbital myositis, an uncommon condition of unknown etiology. However, the patient had taken rosuvastatin, which has been rarely associated with diplopia and ophthalmoplegia, raising the question of whether this case was truly idiopathic.

Immunoglobulin G4-related Disease Accompanied by Peripheral Neuropathy: A Report of Two Cases

Due to its rarity and the limited literature, the clinicopathological characteristics of peripheral nerve involvement in immunoglobulin G4 (IgG4)-related disease are unknown. We present two cases of IgG4-related disease, accompanied by peripheral neuropathy, presenting as unilateral ptosis (case 1) and sclerosing cholangitis (case 2), respectively. In both cases, sural nerve biopsy indicated vasculitis as the underlying pathophysiology; the peripheral neuropathy was refractory to corticosteroid therapy. In contrast to the previously proposed pathomechanism of IgG4-related neuropathy (direct lymphoplasmacytic infiltration), the pathological findings in our cases suggest that vasculitis occurs secondary to systemic autoimmune conditions.

Atypical Cogan Syndrome Featuring Orbital Myositis and Dacryoadenitis

A 39-year-old male presented with bilateral hearing loss and progressive left eye vision loss over a 14-month period. The development of systemic symptoms including arthralgias, enlarged lymph nodes, and profound leg weakness, prompted a workup for lymphoproliferative disease, infection, and autoimmune inflammatory conditions which was unrevealing. Subsequently, the right visual acuity declined from 20/25 to 20/70 and the left to hand motions due to corneal interstitial keratitis. There was limitation of left infraduction. Neuroimaging revealed dural thickening of the internal auditory canals, cavernous sinuses, cerebellum, and along the optic nerves. There was fusiform enhancing enlargement of the left inferior and medial rectus muscles and pathologic enlargement of the left lacrimal gland. Biopsy of the left lacrimal gland and left inferior rectus revealed fibrosis and lymphocytic infiltration. The patient was diagnosed with atypical Cogan syndrome and treated with oral prednisone, with improvement in visual acuity of the right eye, motility of the left eye, and systemic weakness.

Unilateral Ptosis, Proptosis, and Orbital Myositis After Shingles Vaccination

Vaccinations for shingles are recommended for most adults over 60 years of age and are typically well tolerated. The present case describes acute onset of unilateral ptosis, proptosis, and orbital myositis developing within days after administration of shingles vaccination. The episode resolved to baseline after 1 week of treatment with steroids. To the authors' knowledge, this is first reported case of orbital inflammation following shingles vaccination. Given the temporal relationship and rapid response to treatment, this may represent an autoimmune reaction to the shingles vaccine.

New Onset of Unilateral Orbital Myositis following Mild COVID-19 Infection

Purpose: The authors present a case of unilateral orbital myositis of new onset following COVID-19 without a severe course.Methods: The patient had been received topical treatment with a preliminary diagnosis of conjunctivitis but no recovery had been noticed. The history revealed that the ocular signs had started 1 week after the COVID-19.Results: The examination revealed sectoral hyperemia of the temporal region in the bulbar conjunctiva together with marked limitation of right inward gaze. MRI of the orbits demonstrated diffuse fusiform enhancing enlargement of the right lateral rectus and superior rectus. The results of the laboratory tests and examination findings were normal. Systemic corticosteroids were started for the orbital myositis.Conclusions: Although conjunctivitis is the more common ocular disease following COVID-19, the possibility of orbital myositis should be considered in cases with resistance to topical treatment and/or gaze limitation. The possible role of orbital myositis as a trigger for COVID-19 could be explained with an immune-mediated mechanism.

Orbital giant cell myositis is an unusual and potentially lethal cause of bilateral ophthalmoplegia - A case report and literature review

We present a case of orbital giant cell myositis (OGCM), presenting with bilateral subacute progressive ophthalmoplegia and optic nerve dysfunction. An early extraocular muscle biopsy confirmed the diagnosis and guided appropriate management. Comprehensive investigation excluded any underlying systemic disease, including myocarditis. Twenty two months after presentation, the patient remains well on azathioprine with complete resolution of orbital signs.

Immune checkpoint inhibitor-associated myopathy: a clinicoseropathologically distinct myopathy

Immune checkpoint inhibitors have revolutionized the landscape of cancer treatment. Alongside their many advantages, they elicit immune-related adverse events, including myopathy, which potentially result in substantial morbidity if not recognized and treated promptly. Current knowledge of immune checkpoint inhibitor-associated myopathy is limited. We conducted a 5-year retrospective study of patients with immune checkpoint inhibitor-associated myopathy. Clinical features, survival and ancillary test findings were analysed and compared with those of immune-mediated necrotizing myopathy patients without immune checkpoint inhibitor exposure seen during the same time period. We identified 24 patients with immune checkpoint inhibitor-associated myopathy (median age 69 years; range 28-86) and 38 patients with immune-mediated necrotizing myopathy. Ocular involvement occurred in 9/24 patients with immune checkpoint inhibitor exposure, without electrodiagnostic evidence of neuromuscular transmission defect, and in none of the immune-mediated necrotizing myopathy patients (P < 0.001). Myocarditis occurred in eight immune checkpoint inhibitor-associated myopathy patients and in none of the immune-mediated necrotizing myopathy patients (P < 0.001). Median creatine kinase was 686 IU/l in the immune checkpoint inhibitor cohort (seven with normal creatine kinase) compared to 6456 IU/l in immune-mediated necrotizing myopathy cohort (P < 0.001). Lymphopenia was observed in 18 and 7 patients with and without immune checkpoint inhibitor exposure, respectively (P < 0.001). Myopathological findings were similar between patients with and without immune checkpoint inhibitor exposure, consisting of necrotic fibres with no or subtle inflammation. Necrotic fibres however arranged in clusters in 10/11 immune checkpoint inhibitor-associated myopathy patients but in none of the immune checkpoint inhibitor-naïve patients (P < 0.001). Despite the lower creatine kinase levels in immune checkpoint inhibitor-exposed patients, the number of necrotic fibres was similar in both groups. Immune checkpoint inhibitor-associated myopathy patients had a higher frequency of mitochondrial abnormalities and less number of regenerating fibres than immune-mediated necrotizing myopathy patients (P < 0.001). Anti-hydroxy-3-methylglutaryl-CoA reductase or signal recognition particle antibodies were absent in patients with immune checkpoint inhibitor exposure but positive in two-thirds of immune checkpoint inhibitor-naïve patients. Most patients with immune checkpoint inhibitor-associated myopathy responded favourably to immunomodulatory treatments, but four died from myopathy-related complications and one from myocarditis. Intubated patients had significantly shorter survival compared to non-intubated patients (median survival of 22 days; P = 0.004). In summary, immune checkpoint inhibitor-associated myopathy is a distinct, treatable immune-mediated myopathy with common ocular involvement, frequent lymphopenia and necrotizing histopathology, which contrary to immune-mediated necrotizing myopathy, is featured by clusters of necrotic fibres and not accompanied by anti-hydroxy-3-methylglutaryl-CoA reductase or signal recognition particle antibodies. Normal or mildly elevated creatine kinase level does not exclude the diagnosis.

Orbital disease in neuro-ophthalmology

PURPOSE OF REVIEW

Orbital disease represents a diverse spectrum of pathology and can result in a variety of neuro-ophthalmic manifestations. The aim of this review is to provide updates on recent advances in our understanding of orbital disease secondary to thyroid eye disease, myositis, IgG4-related disease, sarcoidosis, granulomatosis with polyangiitis and various tumours.

RECENT FINDINGS

With regards to thyroid eye disease, there have been recent advances in the development of steroid-sparing therapies, new modalities for objectively monitoring disease activity and increased understanding of the role of environmental risk factors. There has been interest in characterizing the clinical course and underlying mechanism of optic nerve disease secondary to orbital disorders, which has led to advances in how we monitor for and prevent permanent vision loss. Increased knowledge of orbital tumour subtype histopathology and the development of novel classification systems has had prognostic value and aided medical decision-making.

SUMMARY

Orbital disease occurs secondary to a wide variety of diseases and can lead to neuro-ophthalmic manifestations with significant morbidity. Advances in our understanding of different subtypes of orbital disease have improved our ability to treat these potentially debilitating conditions.

Histopathologic Findings in Idiopathic Orbital Myositis

PURPOSE

To report the histologic and clinical features of idiopathic orbital myositis (IOM) patients who underwent extraocular muscle (EOM) biopsy over 20 years, to provide the first methodical reference to the expected histopathologic findings, and to discuss the histopathologic differences from common differential diagnoses.

DESIGN

Cohort study.

PARTICIPANTS

All patients with a diagnosis of IOM who underwent EOM biopsy from 2000 through 2019 were included. Patients who had a different final diagnosis were excluded.

METHODS

Tissue samples of EOM and medical records of all participants were reviewed.

MAIN OUTCOME MEASURES

Histopathologic features of muscle biopsy, including tissue morphologic features and cellular composition.

RESULTS

Thirteen patients met both inclusion and exclusion criteria, and their tissue samples were revisited. Nine patients showed histopathologic findings that suggested a conclusive diagnosis of IOM, and the study focused on them. The average age at presentation was 49 years, and 66.7% of patients were women. The most commonly biopsied EOM was the medial rectus (44.4%). The most common indications for biopsy were nonresolving orbital disease with inadequate response to corticosteroids (44.4%) or a high suspicion of malignancy because of known pre-existing systemic malignancy or the presence of an atypical orbital mass in addition to enlarged muscles (44.4%). The histopathologic findings that suggested a diagnosis of IOM were splaying of muscle fibers by inflammatory infiltrates (n = 9) and mild fibrosis (n = 8) in the endomysium or replacing muscle fibers, with no granulomas or vasculitis. The inflammatory infiltrates identified were of chronic inflammatory cells, consisting of lymphocytes (n = 9), plasma cells (n = 6), and histiocytes (n = 6). Other less commonly identified cells were eosinophils (n = 4), polymorphonuclears (n = 1), and giant cells (n = 1). Muscle fiber degeneration or regeneration was evident in 5 patients. Four patients from the initial cohort showed inconclusive histologic findings on revision and were reassigned as suspected IOM.

CONCLUSIONS

The histopathologic features of involved muscles in IOM resemble those seen in idiopathic orbital inflammation and differ from those seen in common differential diagnoses. Extraocular muscle biopsy should be strongly considered whenever the presentation of orbital myositis is not typical or when significant underlying conditions are a possibility.

Granulomatosis with polyangiitis presenting as recurrent, multifocal orbital myositis

A 43-year-old woman was referred with a 10 month history of persistent pain in the left orbit. Two years prior, she experienced similar pain in the right orbit. Magnetic resonance imaging (MRI) at the time revealed an enlarged right medial rectus muscle. She was diagnosed with idiopathic orbital myositis and was successfully treated with oral corticosteroids. A year later, she developed symptoms in the left orbit with similar imaging findings. For ten months, she remained on high dose corticosteroids for presumed left medial rectus myositis before presenting to our service. Computed tomography (CT) imaging after corticosteroid taper revealed enlarged left medial rectus and left lateral rectus muscles. Orbital biopsy established a diagnosis of granulomatosis with polyangiitis (GPA), for which she was successfully treated with rituximab. This case underscores the importance of not only proceeding with biopsy in atypical cases of orbital myositis but to also taper steroids prior to biopsy.

Necrotizing myositis in a rectus muscle arising in the setting of long-standing Langerhans cell histiocystosis and recent dabrafenib treatment

Purpose

to describe an unusual case of necrotizing myositis in a rectus muscle, possibly related to BRAF inhibitor therapy.

Observations

An 18-year old man with neurodegenerative Langerhans cell histiocytosis (LCH), recently started on the BRAF inhibitor dabrafenib, presented with right eye pain. Magnetic resonance imaging (MRI) orbits revealed a rectus muscle mass concerning for LCH recurrence or malignancy. Dabrafenib was stopped, and incisional biopsy of the mass was performed. The mass was absent on post-operative MRI, so no further treatment was pursued. Histopathologic evaluation was initially concerning for sarcoma, but on further analysis, appeared more consistent with necrotizing myositis. The mass did not recur, nor did the patient develop other signs or symptoms concerning for myositis or malignancy over a 24-month follow-up period.

Conclusions

Necrotizing myositis has not been previously described in a rectus muscle or with BRAF inhibitor use, though myalgias and malignancies are established side effects. Necrotizing myositis may masquerade as sarcoma and should be on the differential diagnosis for a new mass in the setting of dabrafenib therapy.

Vertical restrictive strabismus associated with proptosis: Similar clinical signs, different etiopathogenetic causes. A report of three patients

PURPOSE

To report the different uncommon pathogenesis of three cases of severe vertical restrictive strabismus associated with progressive unilateral proptosis with similar clinical features.

METHODS

Case series of three patients who presented to the Orbit Outpatient Service of Policlinico Gemelli with a history of left progressive unilateral proptosis, slowly worsening vertical strabismus and the left eye fixed in downward position. A thorough hematologic work up was performed. All patients underwent complete abdomen ultrasonography, orbital contrast enhanced magnetic resonance imaging, forced duction test under general anesthesia, and orbital biopsy.

RESULTS

Patients were 30, 60, and 46 years old respectively. MRI showed left inferior rectus enlargement in two cases and superior rectus enlargement in one case, with contrast enhanced combined muscle belly and tendon enlargement in all cases. Patients underwent forced duction test, muscle weakening (in two cases), and muscle biopsy with histopathologic examination. The superior rectus appeared infiltrated by an undifferentiated high-grade pleomorphic sarcoma, whereas the two inferior recti were positive for idiopathic orbital inflammatory disease with fibrosis areas and neuromuscular choristoma, respectively.

CONCLUSION

Although proptosis and acquired vertical restrictive strabismus are most commonly associated with thyroid associated orbitopathy (TAO), they can also be a manifestation of many other conditions and the differential diagnosis can be particularly challenging. The three reported cases presented indeed with similar clinical features but had three distinct underlying orbital etiologies, two of which were extremely uncommon.

Non-specific orbital inflammation: Current understanding and unmet needs

Non-specific orbital inflammation (NSOI) is a noninfectious inflammatory condition of the orbit. Although it is generally considered the most common diagnosis derived from an orbital biopsy, it is a diagnosis of exclusion, meaning that the diagnosis requires exclusion of a systemic process or another identifiable etiology of orbital inflammation. The clinical diagnosis of NSOI is ill-defined, but it is typically characterized by acute orbital signs and symptoms, including pain, proptosis, periorbital edema, chemosis, diplopia, and less commonly visual disturbance. NSOI poses a diagnostic and therapeutic challenge: The clinical presentations and histological findings are heterogeneous, and there are no specific diagnostic criteria or treatment guidelines. The etiology and pathogenesis of NSOI are poorly understood. Here we recapitulate our current clinical understanding of NSOI, with an emphasis on the most recent findings on clinical characteristics, imaging findings, and treatment outcomes. Furthermore, gene expression profiling of NSOI and its implications are presented and discussed.