Lymphomas and metastases of the extra-ocular musculature

Practical Approach to Orbital Lesions by Anatomic Compartments

A wide range of pathologic conditions can originate in the orbit. While it is common to approach the differential diagnosis based on disease categories, such as neoplastic and inflammatory, segmenting the orbit into anatomic compartments can direct the radiologist toward the most common pathologic conditions for each manifestation and space. The orbit can be divided into intraconal, conal, and extraconal compartments. Additionally, the optic nerve sheath complex and lacrimal apparatus can be partitioned into separate compartments due to their unique functions and pathologic features. By using this anatomic approach, the authors review the most common pathologic conditions affecting the orbit and discuss clinical and imaging findings that can guide the differential diagnosis for lesions with similar appearances. Published under a CC BY 4.0 license. Supplemental material is available for this article.

Review article: Diagnosis and management of enlarged extraocular muscles

Extraocular muscle (EOM) enlargement may be due to a variety of causes. These causes can be classified in three ways: according to pathogenesis and histopathological features, according to the site, and according to the clinical features. Diagnosis of the cause is dependent upon history, clinical examination, and investigations. Imaging with computed tomography or magnetic resonance imaging and muscle biopsy is typically necessary to make the correct diagnosis. Treatment of the patient must be directed toward the specific cause. This review emphasizes important clinical and pathological guidelines for appropriate diagnosis and treatment of patients with EOM enlargement.

Graves' Eye Disease: Clinical and Radiological Diagnosis

Graves' disease is an autoimmune disorder in which hyperthyroidism results in various systematic symptoms, with about 30% of patients presenting with Graves' eye disease (GED). The majority of patients with GED develop mild symptoms, including eyelid retraction, exposure of the globe, superior rectus-levator muscle complex inflammation, and fat expansion, leading to exophthalmos. More severe cases can result in extraocular muscle enlargement, restricted ocular movement, eyelid and conjunctival edema, and compression of the optic nerve leading to compressive optic neuropathy (CON). GED severity can be classified using the Clinical Activity Score, European Group on Graves' Orbitopathy scale, NO SPECS Classification system, and VISA system. CT and MRI aid in the diagnosis of GED through the demonstration of orbital pathology. Several recent studies have shown that MRI findings correlate with disease severity and can be used to evaluate CON. Mild cases of GED can be self-limiting, and patients often recover spontaneously within 2-5 years. When medical treatment is required, immunomodulators or radiotherapy can be used to limit immunologic damage. Surgery may be needed to improve patient comfort, preserve the orbit, and prevent vision loss from optic nerve compression or breakdown of the cornea.

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.

Extrathyroidal Manifestations of Thyroid Disease: Graves Eye Disease

Graves disease is an autoimmune disorder caused by the breakdown of immune tolerance to thyroid antigens against the TSH receptor. In approximately 25% of patients, an inflammatory condition, Graves eye disease (GED), affects the orbital soft tissues. About 60% of patients develop mild symptoms including fat expansion and inflammation of the levator muscle complex with resultant proptosis, eyelid retraction, and exposure of the globe. The remaining patients experience enlargement of one or more of the extraocular muscles, leading to conjunctival and eyelid edema and congestion, restricted ocular movement with resultant diplopia, and optic nerve compression leading to compressive optic neuropathy.

Choroidal Melanoma Metastatic to the Contralateral Medial Rectus After Orbital Exenteration

A 78-year-old Caucasian woman presented with pain in her right and only eye that was worse on abduction. Her history was significant for a choroidal melanoma affecting her left eye for which she underwent an orbital exenteration 12 years previously. Computed tomography and magnetic resonance imaging of the right orbit identified a mass lesion affecting the medial rectus, suspicious for metastatic melanoma. A histopathological diagnosis of metastatic melanoma was subsequently made following biopsy of the right medial rectus.

Metastasis to the extraocular muscles: a case report, literature review and pooled data analysis

Metastasis to the extraocular muscles (EOM) is rare. The existing literature comprises only of isolated case reports therefore a summative description of these lesions is lacking. This study presents a case of bilateral rectus muscle metastasis from malignant melanoma. Furthermore a literature review and pooled data analysis is undertaken with 43 articles encompassing 77 patients and 101 eyes. Mean age was 53 years, 54% were male, 66% had unilateral involvement and 34% had bilateral involvement. The primary malignancies were melanoma (n = 17, 22%), breast (n = 15, 15%) and carcinoid (n = 11, 14%). A single muscle was involved in 56 eyes (67%) and multiple muscles in 27 eyes (33%). Lateral rectus was most commonly affected (n = 44, 53%). Presenting symptoms included restricted eye movements (n = 48, 62%), proptosis (n = 45, 58%), diplopia (n = 27, 35%) and pain (n = 18, 23%). Scattered case reports have previously made it difficult to characterise this phenomenon thus a pooled data analysis is presented.

Review of extraocular muscle biopsies and utility of biopsy in extraocular muscle enlargement

Aims

To review the distribution of pathology in extraocular muscle (EOM) biopsies performed at a tertiary orbital centre, identify clinical and imaging features which are associated with benign or malignant diseases and indicate when biopsy is necessary for EOM enlargement.

Methods

Retrospective case series including 93 patients with EOM enlargement who underwent an EOM biopsy. Clinical, radiological and histopathological information was recorded from the medical records. Statistical analysis was used to compare variables between patients with malignant and benign biopsies.

Results

The median age of subjects was 61.1 years. Forty-eight cases (52%) were benign and 45 (48%) were malignant. Those with malignant pathology were significantly older (P<0.0001). Males were more likely affected by a benign disease and females by a malignancy (P=0.029). A history of malignancy (P<0.0001) and diplopia (P=0.029) were significant factors in predicting a malignancy. Pain (P=0.005) and eyelid erythema (P=0.001) were more likely in benign conditions. Idiopathic orbital inflammation was the most common benign diagnosis and lymphoma the most common malignancy.

Conclusions

Biopsy is warranted in those with an atypical presentation of EOM enlargement or suspected of having a malignancy. Some features such as age, gender, pain, diplopia, history of malignancy and eyelid erythema may help indicate a particular diagnosis; however, clinical features and imaging findings are often not pathognomonic of each disease.

Orbital ultrasonography in the diagnosis of neoplastic extraocular muscle enlargement

Neoplastic infiltration of the extraocular muscle (EOM) is a rare condition which can pose a diagnostic dilemma due to its rarity and overlapping ultrasonographic features with orbital myositis. The ultrasonographic features of neoplastic enlargement of EOM have not been systematically studied and previously have been described in only a few case reports. Orbital ultrasonography, in conjunction with the pattern of ocular misalignment, was assessed for its potential role in identifying patients with neoplastic EOM enlargement. Retrospective chart review of patients with neoplasm and myositis. The clinical features of 8 patients with neoplastic infiltration of the EOM were compared to 15 patients with myositis. In the neoplastic group the width of the EOM was (10.5 mm) almost twice the normal width of the muscle with myositis (p < 0.001). All the muscles in the neoplastic category were low to medium reflective. Paretic deviation was seen in 4/8(50%), purely restrictive in 2/8 (25%) and combined pattern in 2/8 (25%) were noted. In the myositis group the average EOM enlargement was 5.8 mm and all muscles showed low reflectivity. Although ultrasonographic features overlapped between the 2 groups paretic deviations were more common in the neoplastic group versus the myositis group (50% versus 7%). Neoplastic muscle enlargement tends to be larger with paretic deviations of ocular motility seen clinically. These findings in a patient with EOM enlargement should raise the suspicion of neoplasm as the etiology and further work up should be considered.

Extramedullary plasmacytoma of the lateral rectus muscle

Plasmacytoma is an uncommon presentation of plasma cell malignancy, especially in the absence of multiple myeloma. Orbital plasmacytomas generally originate from bone, although few cases in the literature report orbital extramedullary plasmacytomas. We present the case of a 68-year-old man found to have a solitary extramedullary plasmacytoma in the lateral rectus muscle without further evidence of multiple myeloma. This case demonstrates a rare presentation for such a malignancy, and a review of the literature highlights the importance of proper workup and close monitoring to rule out multiple myeloma to guide management.

Whole body computed tomographic characteristics of skeletal and cardiac muscular metastatic neoplasia in dogs and cats

Muscular metastatic neoplasia has been reported to be rare in domestic animals, however previous studies were based primarily on necropsy findings. The purpose of this retrospective study was to describe whole body computed tomography (CT) characteristics of confirmed muscular metastases in a cohort of dogs and cats presented for oncology evaluation. Medical records of 1201 oncology patients were reviewed. Included animals underwent pre and postcontrast whole body CT, and CT-guided tru-cut biopsy or fine needle aspiration of one or more metastatic lesions. Twenty-one dogs and six cats met inclusion criteria, representing 2.08% of all canine oncology patients and 3.1% of all feline oncology patients. Mean age was 9.6 years. Postcontrast CT characteristics included well-demarcated, oval-to-round lesions with varying enhancement patterns: ring enhancing (n = 16), heterogeneously enhancing (n = 8), or homogeneously enhancing (n = 5). Five animals showed concurrent and varying nodular patterns. In seven cases (five dogs and two cats), one single muscular nodule was observed. In 20 cases, two or more lesions were observed. In two cases, cardiac hypodense nodules were observed in the postcontrast CT, while appearing isodense in the precontrast study. Necropsy confirmed neoplasia in both of them. Locations of muscular metastases included epaxial/paraspinal muscles of the cervical, thoracic, and lumbar spine (n = 18), superficial muscles of the thoracic wall (n = 13), scapular/shoulder region (n = 3), hind limb (n = 3), and abdominal wall muscles (n = 1). Findings supported the use of pre and postcontrast whole body CT for oncologic staging in dogs and cats, especially for primary tumors characterized by a high metastatic rate.

Bilateral metastatic melanoma to the extraocular-muscles simulating thyroid eye disease

We report a case of bilateral metastatic melanoma to the extraocular muscles that simulated thyroid eye disease. A 71-year-old man presented with bilateral painless axial proptosis, lid retraction and left gaze restriction. Orbital CT scan demonstrated enlargement of the extraocular muscles with tendon sparing, consistent with thyroid eye disease. However, thyroid function tests and antithyroid antibodies were normal. Systemic review including orbital MRI scan determined the correct diagnosis of metastatic melanoma to the orbit. Metastatic melanoma to the orbit can simulate thyroid eye disease.