Pictorial Review of Orbital Tumors and Tumor-like Lesions eEdE-155a Viet Nguyen, MD Maria Valencia, MD Achint Singh, MD Wilson Altmeyer, MD Carlos Bazan III, MD Bundhit Tantiwongkosi, MD Disclosure Statement The authors have no financial interest to disclose. Objectives 1) Review basic anatomy of the orbit 2) Illustrate characteristic imaging findings of orbital tumor and tumor-like lesions with respect to orbital compartments Table of Contents Introduction / Anatomy Globe Intraconal Extraconal Conal Multicompartment Summary Click to proceed directly to section of choice. Introduction • Orbital tumors and tumor-like lesions have a spectrum of imaging findings with distinct outcome and treatment planning • Compartmental approach of orbital lesions helps guide diagnostic consideration • CT and MR play crucial role in diagnosis, treatment planning, follow up and surveillance Anatomy Click to highlight structure. Extraconal Lacrimal Gland Superior Rectus Inferior Rectus Medial Rectus Conal Lateral Rectus Superior Oblique Inferior Oblique Levator Palpebrae Superioris Intraconal Optic Nerve Ophthalmic Artery Superior Ophthalmic Vein Globe Superior Orbital Fissure Optic Canal Anatomic Considerations Orbital Foramina Contents Superior Orbital Fissure Cranial nerve III, IV, V1, VI Superior ophthalmic vein Middle meningeal artery, orbital branch Sympathetic fibers Optic Canal Optic nerve Ophthalmic artery Sympathetic fibers Infraorbital Canal Adapted from: Som, Peter M., and Hugh D. Curtin. "Normal Orbital Anatomy." Head and Neck Imaging. St. Louis, MO: Mosby, 2011. 549-51. Cranial nerve V2 Infraorbital artery & vein http://commons.wikimedia.org/wiki/File:Schematic_diagram_of_the_human_ey e_en.svg http://commons.wikimedia.org/wiki/File:713_Bones_Forming_Orbit.jpg Ocular Melanoma • • Enhancing choroidal mass with increased T1W MR signal; most common primary ocular tumor adult Enhancement on MR distinguishes tumor from commonly associated retinal detachment Sagittal oblique MR images show an avidly enhancing, high T1/low T2 signal mass in the posterior globe extending to the adjacent sclera & causing partial retinal detachment (no enhancement). Choroidal Melanoma Coronal post contrast T1W MR image reveals a focal linear area of enhancement at the superior nasal aspect of the right globe, within the choroid layer. This was proven to be choroidal melanoma on histology. The tumor can be subtle in this case; therefore, correlation between imaging & fundoscopic findings are crucial. Nodular Scleritis Coronal & sagittal MR images of the orbits show an anterior right scleral lesion with intermediate T1/low T2 signal intensity & contrast enhancement. This was a case of nodular scleritis mimicking a neoplasm in a patient with juvenile rheumatoid arhritis. Thickening & enhancement of the left globe also represent scleritis. Intraconal Orbital Hemangioma • • • Well-defined, ovoid, enhancing mass with patchy enhancement Most common adult orbital mass, typically intraconal Hemangiopericytoma can have similar imaging appearance, but is rare MR imaging of the orbits reveals a well-defined, round intraconal mass displacing the optic nerve. The lesion shows low T1, high T2 signal intensity & characteristic patchy enhancement. Optic Nerve Sheath Meningioma • • Enhancing mass encasing intraorbital optic nerve with calcifications Gradual onset of proptosis & decreased vision in middle-aged women Axial NECT image reveals a calcified optic nerve sheath menignioma surrounding the intraorbital optic nerve resulting in proptosis. Avid homogenous enhancement is seen on axial MR T1W image. The optic nerve is normal in size but can have abnormal MR signal. Optic Nerve Glioma • • • Fusiform optic nerve mass with variable involvement of posterior pathway Variable enhancement Bilateral intraorbital lesions are highly associated with NF1 Axial MR images of a patient with neurofibromatosis 1 show T1 isointense fusiform enlargement & kinking of the optic nerves. Note the avid enhancement of the right & minimal enhancement of the left optic nerve gliomas. CN III Schwannoma • • Enhancing, tubular soft tissue mass along the course of CN III with smooth bony remodeling Can have cystic formation Axial & coronal MR imaging shows a tubular, intraconal orbital mass with low T1/high T2 signal & intense enhancement in the superior orbital fissure extending posteriorly into the cavernous sinus. Note the medial displacement of the tortuous CN II. Lymphoma • • • Avidly enhancing soft tissue that molds to & encases orbital structures Prompts whole body staging & surveillance for systemic lymphoma Important differential consideration for any orbital mass MR imaging of the orbits in a patient with known anaplastic large cell lymphoma of the head, face & neck shows increased T2 signal with enhancement involving the intraorbital left optic nerve & surrounding intraconal fat. There is restricted diffusion of the optic nerve on DWI & ADC map. Leptomeningeal Carcinomatosis Axial post contrast T1W MR image reveals symmetric enhancement of optic nerve sheaths & intraconal fat. This was a histologically proven case of leptomeningeal carcinomatosis in a 44 yo female patient with HIV & metastatic leiomyosarcoma. Orbital Carcinoid Tumor • • Represent 4%-5% of all orbital metastasis May show elevated urinary 5-HIAA without hepatic metastasis Multiplanar contrast-enhanced MR T1W images show avidly enhancing intraconal mass displacing the optic nerve medially. This was a case of orbital metastasis from primary abdominal carcinoid tumor. Extraconal Cavernous Hemangioma • • • Well-defined, ovoid, enhancing mass with patchy enhancement Most common adult orbital mass, typically intraconal Hemangiopericytoma can have similar imaging appearance, but is rare MR imaging of the orbits illustrates a well-defined, right lateral extraconal mass with high T2, low T1 signal intensity & characteristic patchy enhancement. CN V1 Schwannoma Coronal & axial MR images demonstrate an orbital mass with heterogeneous high T2 signal & intense enhancement in the right superomedial extraconal space that displaces the globe & superior rectus muscle inferolaterally. This was proven to be schwannoma in the expected course of CN V1. Acute Myelogenous Leukemia • • Homogenous enhancing soft tissue in patients with known systemic disease Extramedullary hematopoeisis can have similar appearance in same at-risk patient population Axial & coronal MR imaging of the orbits in a pediatric patient with AML demonstrates extraconal soft tissue masses with low T1/low T2 signal intensity & homogenous enhancement. Orbital Lymphoplasmacytic Lymphoma Coronal & axial MR images of the orbits reveal a homogenously, enhancing mass with low T1/high T2 signal intensity in the right superior extraconal compartment at the level of the lacrimal gland resulting in inferior displacement of the globe. Focus of low T2W signal intensity represents lymphoid tissue. Wegener Granulomatosis • • • Systemic necrotizing vasculitis, with renal & respiratory involvement Paranasal sinus & orbital involvement (most common extrasinonasal site) with bone destruction, commonly bilateral Difficult to differentiate from lymphoma or sarcoidosis on imaging Axial & coronal MR imaging of the orbits demonstrates a medial intraconal soft tissue mass with low T1/low T2 signal intensity & avid enhancement. This was a proven case of orbital extension of Wegener granulomatosis. Orbital Subperiosteal Abscess • • • Lenticular, rim-enhancing fluid collection along the medial extraconal orbit, with adjacent ethmoid sinusitis Orbital cellulitis & proptosis; may be 1st sign of acute to subacute sinusitis in children Restricted diffusion on MR increases diagnostic confidence Axial CECT imaging through the orbits reveals a subperiosteal abscess extending into the medial extraconal orbit & causing displacement of the medial rectus. Note the ethmoid sinusitis. Periorbital edema & mild proptosis are also evident. Intraorbital Abscess Axial CECT image of the orbits reveals right proptosis & lateral periorbital edema with a rim enhancing fluid collection in the right lateral extraconal space. Axial & coronal MR images demonstrate a rim enhancing fluid collection with high T2W signal intensity abutting & displacing the right lateral rectus muscle. There is restricted diffusion on DWI & ADC map. Lacrimal Lymphoma • • Pliable mass arising from lacrimal gland. Can be multiple masses & predominantly MALT type Axial & coronal MR images reveal an enlarged, intensely enhancing lacrimal gland mass with low T1/high T2 signal intensity. This was found to be diffuse large B-cell lymphoma of the lacrimal gland. Lacrimal Gland Pleomorphic Adenoma • • Unilateral, well-marginated, oval lacrimal mass with characteristic scalloped bony remodeling of lacrimal fossa Slow growing & absence of pain Multiplanar MR images reveal an enlarged lacrimal gland with low T1/low T2 signal intensity. Lacrimal Adenoid Cystic Carcinoma • • Irregular mass in the lacrimal fossa with bony erosion Difficult to distinguish from benign lacrimal processes without bone destruction Axial & coronal MR images reveal an avidly enhancing, T2 hyperintense heterogeneous mass with lobulated, well-defined margins arising from the lacrimal gland. Biopsy demonstrated adenoid cystic carcinoma of the lacrimal gland. IgG4 Related Disease • • Bilateral chronic dacryoadenitis > submandibular sialadenitis > parotiditis with variable orbital inflammatory pseudotumor, myositis, perineural disease Characteristically hypointense on T2WI due to high cellularity & fibrosis Axial NECT image of the orbits reveal enlarged lacrimal glands. They demonstrate intermediate T1/T2 signal intensity & avid enhancement. Dacrocystocele • • • Well-circumscribed cyst arising from the lacrimal sac, typically self-limited 25% bilateral with variable intranasal extension Bilateral cysts may cause nasal obstruction at the level of inferior meatus Axial NECT images of a 22-day-old newborn reveal a cystic lesion in the medial orbit at the location of the lacrimal sac. Note the dilated nasolacrimal sac. Dermoid Cyst • • Well-circumscribed, nonenhancing unilocular cystic lesion containing lipid Can have capsular calcification Axial imaging of the orbits reveals an ovoid, well-defined, right lateral extraconal mass causing medial displacement of the lateral rectus. This mass demonstrates fatty attenuation (-20 HU), hyperintensity on T1W, & hypointensity on contrastenhanced T1W fat suppression. Extraconal Dermoid Cyst/Lipoma Axial & coronal NECT images of the orbits reveal a well-defined mass with fatty attenuation along the lateral aspect of the left globe, anterior to the attachment of the lateral rectus muscle. Note the punctate calcification at the medial aspect of the mass, abutting the globe. Extraocular Muscle Metastasis Coronal & axial CECT images show an enlarged, enhancing left lateral rectus muscle with adjacent conal fat stranding. There is mild left proptosis. Axial & coronal MR images reveals isotense T1/hyperintense T2, & avidly enhancing lateral rectus muscle. The patient was a 31 yo female with metastatic breast cancer & left orbital cellulitis not responding to antibiotics. Idiopathic Inflammatory Pseudotumor • • • Ill-defined masslike enhancing soft tissue involving any compartment of the orbit; 25% bilateral Diagnosis of exclusion; biopsy for atypical onset, poor response or recurrence Typically painful Axial & coronal MR imaging through the orbits shows a poorly-defined T1 hypointense/T2 hyperintense mass with heterogeneous enhancement encasing the medial rectus with involvement of multiple compartments. There is mild proptosis & lateral displacement of the globe. Lymphangioma • • Ill-defined, lobulated lymphatic & venous malformation spanning multiple compartments Characteristic fluid-fluid levels, blood products, & variable irregular enhancement MR imaging of the orbits shows an irregular, lobulated retrobulbar mass with characteristic fluidfluid levels & multi-compartment involvement. Low T1/heterogenous high T2 signal intensity & enhancement are seen. Metastatic Breast Cancer Axial & coronal MR images show T1 hypointense, enhancing metastatic breast cancer filling multiple compartments of the bilateral orbits. Note the prominent right enophthalmos secondary to classic schirrous changes. Summary • It is crucial for radiologists to be familiar with the imaging features of orbital masses. Some have characteristic findings, e.g. optic nerve glioma, optic nerve sheath meningioma, cavernous hemangioma, etc. • Compartmental approach to assessing orbital lesions helps guide diagnostic consideration • Correlation between imaging and physical findings are paramount References • Ansari, Sameer A., and Mahmood F. Mafee. "Orbital cavernous hemangioma: role of imaging." Neuroimaging clinics of North America 15.1 (2005): 137-158. • Chung, Ellen M., et al. "From the Archives of the AFIP Pediatric Orbit Tumors and Tumorlike Lesions: Osseous Lesions of the Orbit 1." 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