Orbital tumours and tumour-like lesions: exploring the armamentarium of multiparametric imaging

Abstract

Although the orbit is a small anatomical space, the wide range of structures present within it are often the site of origin of various tumours and tumour-like conditions, both in adults and children. Cross-sectional imaging is mandatory for the detection, characterization, and mapping of these lesions. This review focuses on multiparametric imaging of orbital tumours. Each tumour is reviewed in relation to its clinical presentation, compartmental location, imaging characteristics, and its histological features. We herein describe orbital tumours as lesions of the globe (retinoblastoma, uveal melanoma), optic nerve sheath complex (meningioma, optic nerve glioma), conal-intraconal compartment (hemangioma), extraconal compartment (dermoid/epidermoid, lacrimal gland tumours, lymphoma, rhabdomysarcoma), and bone and sinus compartment (fibrous dysplasia). Lesions without any typical compartmental localization and those with multi-compartment involvement (veno-lymphatic malformation, plexiform neurofibroma, idiopathic orbital pseudotumour, IgG4 related disease, metastases) are also reviewed. We discuss the role of advanced imaging techniques, such as MR diffusion-weighted imaging (DWI), diffusion tensor imaging, fluoro-2-deoxy-D-glucose positron emission tomography CT (FDG-PET CT), and positron emission tomography MRI (MRI PET) as problem-solving tools in the evaluation of those orbital masses that present with non-specific morphologic imaging findings. Main messages/Teaching points • A compartment-based approach is essential for the diagnosis of orbital tumours. • CT and MRI play a key role in the work-up of orbital tumours. • DWI, PET CT, and MRI PET are complementary tools to solve diagnostic dilemmas. • Awareness of salient imaging pearls and diagnostic pitfalls avoids interpretation errors.

Keywords: Diffusion weighted imaging (DWI); Magnetic resonance imaging (MRI); Orbit tumours; Positron emission tomography CT (PET CT); Positron emission tomography MRI (MRI PET).

Fig. 1

Schematic illustration of the orbital contents and compartments. Axial and coronal view of the right orbit. Black asterisks indicate the intraconal compartment. Green asterisks indicate the extraconal compartment

Fig. 2

3-year-old boy with right-sided retinoblastoma. a. Axial 3D T2W image of the orbits shows a well-circumscribed retinal mass (solid arrow), which appears very hypointense as compared to the surrounding bright vitreous. Associated retinal detachment/haemorrhage (dashed arrows) appears moderately hypointense. c. Sagittal contrast-enhanced FS T1W image of the same patient shows avid tumour enhancement (arrow). The tumour is limited to the globe. No other lesions were seen intracranially

Fig. 3

50-year-old male patient diagnosed with a left-sided uveal melanoma on ophthalmoscopy. a. Axial contrast-enhanced CT image shows a tiny, avidly enhancing nodule (arrow) along the choroid

Fig. 4

5-year-old boy with NF-I. a. Axial T2W MR image of the orbits shows bilateral ONG (dashed arrows) causing fusiform enlargement and kinking of the optic nerves. A focal T2- hyperintense lesion (arrowhead) is seen in the right mesial temporal lobe. b. Coronal T2WMR image of the same patient shows extension of the bilateral ONG along the intracranial segments of the optic nerves (arrows). c. Axial contrast-enhanced FS TIW MR image of the same patient shows prominent enhancement in the intracanalicular and intracranial segments of bilateral ONG (arrows). There is also avid enhancement in the suprasellar/chiasmatic region (arrowhead) and in the right mesial temporal lesion (arrowhead) in keeping with tumour extension along the optic chiasm and right optic radiation

Fig. 5

41-year-old woman with right-sided progressive vision loss and proptosis. a. Axial T2W image shows a moderately hpointense fusiform lesion originating from the optic nerve sheath encasing the optic nerve (arrow). b. Corresponding axial ADC map from RESOLVE DWI shows restricted diffusion (arrow). Note only minor image deformation. c. ADC map from standard EPI sequence also shows restricted lesion diffusivity (arrow); however, note major image deformation due to susceptibility artefacts. d. Axial contrast enhanced T1W image reveals strong fusiform enhancement along the optic nerve (“tram track sign”, arrow). There was no extension through the orbital apex intracranially. e. Coronal fat saturated T1W image displaying concentric enhancement of the tumour around the compressed optic nerve creating a characteristic “bull’s eye” appearance (arrow). Imaging findings are in keeping with an ONSM. f. DTI 3D tractography reconstruction of the optic nerves reveals normal fibres on the left (fibers are depicted in green due to their anterior- posterior course) and major fibre atrophy on the right (arrow)

Fig. 6

Orbital hemangioma as seen on CT in two different patients. a. Coronal NECT in a 30-year-old male patient shows a well-circumscribed intraconal mass (arrow) with calcified phleboliths. b-d. 50-year-old male patient with an incidentally diagnosed left orbital cavernous hemangioma on an angio-CT performed for stroke. b. NCECT shows a nonspecific intraconal lesion (arrow) without phleboliths. Arterial phase (c) demonstrates initial patchy enhancement (arrow) followed by progressive filling of the lesion in the venous phase (d)

Fig. 7

60-year-old man with left orbital cavernous hemangioma. Coronal STIR image (a) shows a well-circumscribed hyperintense intraconal mass (arrow) causing superior displacement of the left optic nerve (thin arrow). b. ADC map shows moderately hypointense signal within the mass with an ADC value of 1.4 × 10 ⁻³ mm²/s. c. Axial contrast-enhanced TIW image shows initial patchy enhancement. d. Sagittal reformatted image from a contrast-enhanced 3D VIBE acquisition obtained after the T1W sequence shows characteristic progressive filling (arrow). Major mass effect on the optic nerve (thin arrow). The patient underwent surgery, which confirmed the diagnosis of cavernous hemangioma

Fig. 8

42-year-old male with a histologically proven right orbital dermoid. Coronal T1W (a), axial T2W (b), axial T1W (c), axial ADC map (d), and coronal FS contrast-enhanced T1W (e) images show an orbital lesion with an anterior component containing fatty tissue (thick white arrows) and a posterior component containing non-fatty elements (hollow arrows). There are some fluid droplets in the anterior component (thin arrows). Note minor capsular enhancement after gadolinium administration. The ADC values are very low in the anterior part of the lesion (ADC = 0.1 × 10 ⁻³ mm²/s) due to fat and they are very high in the posterior component (ADC = 1.8 × 10 ⁻³ mm²/s) due to fluid. f. DTI 3D tractography reconstruction of the optic nerves (green) viewed from above and from the left. Right optic nerve fibres (white thin arrows) and left optic nerve fibres (green thin arrows) are normal and have similar FA and ADC values. Thick arrow points to the dermoid

Fig. 9

42-year-old female patient with BMT of the left lacrimal gland. a. Axial T2W MR image shows a well-circumscribed polypoid mass (thick arrow) of moderately hypointense signal involving the left lacrimal gland. Note small satellite nodules (thin arrows). b. Corresponding T1W image shows non-specific lesion hypointensity (arrow). c. ADC map reveals increased diffusion (ADC = 1.6 × 10 ⁻³ mm²/s). d. Coronal contrast-enhanced FS T1W MR image of the same patient demonstrates strong enhancement within the mass (thick arrow) and within the peripheral nodules (thin arrows). e. Sagittal reformatted 0.6 mm thin image from contrast-enhanced 3D VIBE better illustrates scalloping of the orbital roof by the peripheral “grape-like” nodules (thin arrows). e. Photomicrograph of the surgical specimen (original magnification 100x, H&E stain) illustrates the characteristic histological features of pleomorphic adenoma with medium sized cells with an eosinophilic cytoplasm and myoepithelial cells (small asterisk) partly surrounded by a myxoid matrix (large asterisk). The peripheral nodules seen on MRI corresponded histologically to pseudopodia and satellite nodules. Bony invasion by pseudopodia was confirmed histologically

Fig. 10

65-year-old male patient with undifferentiated ductal carcinoma of the right lacrimal gland (mammary analog secretory type). a. Axial NECT of the orbits shows a well-circumscribed, hyperdense mass with stippled calcifications involving the right lacrimal gland. The calcifications were misdiagnosed as phleboliths, which led to the initial diagnosis of a cavernous hemangioma. b. Axial T2W MR image of the same patient shows that the lacrimal gland mass has a very hypointense posterior component (thick arrow) and an anterior moderately hypointense portion (thin arrow). c. Corresponding axial T1W MR image shows that the mass is isointense to the rectus muscles. d. ADC map reveals restricted diffusion (ADC = 0.9 × 10 ⁻³ mm²/s), suggesting a malignant tumour. e. Coronal FS contrast-enhanced T1 W image shows moderate tumour enhancement and lobular appearance. f. Photomicrograph (original magnification 100x, H&E stain) shows a highly cellular tumour with atypical nuclei and mitoses and areas of necrosis (asterisk). There were numerous areas of microscopic perineural spread and lymphatic invasion not detected by imaging

Fig. 11

50-year-old male patient with histologically proven ACC of the left lacrimal gland. Axial NECT of the orbits shows a well-circumscribed, slightly hyperdense mass (arrow) involving the left lacrimal gland. There is suggestion of minimal adjacent bony scalloping. b. Coronal contrast-enhanced FS TIW image of the same patient shows avid, homogeneous, contrast enhancement within the mass (asterisk), mimicking a cavernous hemangioma. There is thinning of the overlying left frontal bone (arrow). c. Axial T2W image of the same patient showing intermediate signal within the mass (asterisk) suggesting high cellularity, a feature that is uncommon in hemangioma. The patient underwent surgery, which revealed ACC with multiple areas of microscopic perineural spread not detected by imaging. d. Contrast-enhanced axial T1W image obtained in a different patient 10 years after surgery of an ACC of the left lacrimal gland shows macroscopic perineural tumour recurrence along the supraorbital nerve (arrows). The findings were confirmed histologically

Fig. 12

4-year-old girl with a left orbital RMS. a. Axial T2W MR image of the orbits shows a conal-extraconal polypoid mass of moderately low signal intensity located superior to the left globe. b. ADC map shows restricted diffusion (ADC = 1 × 10 ⁻³ mm²/s), suggestive of malignancy. c. Coronal contrast-enhanced FS T1W MR image shows avid enhancement within the lesion. d. Axial FDG PET/CT image of the same patient shows high SUVs (SUVmean = 6, SUVmax = 9). Although the lesion may mimic a cavernous hemangioma on the T1W and T2W images, the low ADC and the high FDG uptake strongly suggest a malignant tumour. Histology revealed embryonal rhabdomyosarcoma

Fig. 13

80-year-old male patient with lymphoma of the right orbit. a. Axial T1W image of the orbits shows a hypointense, well-demarcated anterior conal-extraconal lesion (arrow). Axial T2W (b) and coronal STIR (c) images demonstrate intermediate signal intensity of the bulky mass (arrows). Note homogenous aspect. ADC map (d) reveals restricted diffusion (arrow) with very low ADC values (ADC = 0.6 × 10 ⁻³ mm²/s) characteristic of lymphoma. Axial contrast enhanced T1W image (e) shows homogenous enhancement of the mass (arrow). There is enhancement of the superior rectus muscle (thin arrow) suggesting possible involvement. However, the ADC map clearly shows that the superior rectus muscle has no restricted diffusion (thin arrows in d and e). f. Coronal fused PET and STIR image from FDG PET/MRI reveals high tracer uptake within the mass (SUVmean = 4.8, SUVmax = 6.7). No other lymphoma manifestations were detected in the body

Fig. 14

35-year-old female patient with painful proptosis, loss of vision, and subcutaneous facial swelling. Biopsy of the face performed in an outside institution suggested inflammatory pseudotumour. a. Coronal STIR image shows an ill-defined, moderately hyperintense lesion involving the entire left orbit (asterisk) and encasing the optic nerve (thin arrow). The subcutaneous hyperintense, poorly defined area on the left (hollow arrow) corresponds to the biopsied region. b. Axial contrast-enhanced FS T1W MR image of the same patient as in a. The left orbital lesion shows diffuse post-contrast enhancement (asterisk). Enhancing soft tissue is seen extending along the left superior orbital fissure into the left cavernous sinus (arrow) and the dura along the left greater wing of sphenoid. c. Axial contrast-enhanced FS T1W image at the level of the maxillary sinus demonstrates perineural spread along the pterygopalatine fossa and maxillary nerve (arrows). Hollow arrows in b and c point at extra-orbital involement. d. ADC map reveals restricted diffusion of the orbital lesion with very low ADC values (ADC = 0.7 × 10 ⁻³ mm²/s) suggesting lymphoma. The optic nerve shows even lower ADC values (thin arrows) due to compression and ischemia. e. Colour coded DTI map shows major reduction of FA values in the left optic nerve (thin arrows). FA values were 0.4–0.5 on the left and 0.56–0.58 on the right. f. FDG PET/CT demonstrates high tracer uptake in the orbit (asterisk), along the superior orbital fissure and in the cavernous sinus and sphenoid (arrows) confirming findings revealed in b. SUVmean = 10, max = 16. Other hypermetabolic lesions were found in the neck nodes, mediastinum, and abdomen. Biopsy of orbital contents revealed NHL

Fig. 15

Two different patients with FD involving the facial and orbital bones. Characteristic ground-glass appearance (asterisks) and expansion of the medullary cavity is seen in both cases on NECT. In b, bony expansion of the right sphenoid wing and of the right anterior clinoid process causes severe narrowing of the right optic canal (arrow), thereby requiring decompressive surgery

Fig. 16

64-year-old female patient with headache and left vision loss underwent MRI. a. Axial T2W image of the orbits shows deformity and expansion of the sphenoid body. The medullary cavity is replaced by tissue with mixed hyperintense (thick arrow)–hypointense (thin arrow) signal. b. Axial T1W image of the same patient shows the lesion to be mainly isointense to brain parenchyma (thick arrow) and with strongly hypointense central areas (thin arrow). On the left, there are hyperintense peripheral regions. c. Axial contrast-enhanced T1W image shows inhomogeneous contrast enhancement (thick arrow) and cystic portions (dashed arrow). d. ADC map reveals increased diffusion (ADC = 2.3 × 10 ⁻³ mm²/s) suggesting a benign lesion (thick arrow). FD was suspected. e. Oblique reformatted axial image from 3D T2W sequence shows compression of the left optic nerve (thin arrow) at the level of the optic canal. f. Axial NECT image shows ground-glass appearance and irregular ossification of the involved bones. Part of the lesion was resected to decompress the right optic nerve. Histology revealed psammomatous variant of FD

Fig. 17

15-year-old girl with a left orbital VLM. a. Axial FS T2W image shows a mutliloculated cystic lesion involving the intraconal and extraconal compartments of the left orbit (arrow). The strongly hypointense septae of the VLM show hemosiderin staining. b. Contrast-enhanced FS T1W MR image of the same patient shows minimal enhancement (arrow) along the intervening septae of the VLM

Fig. 18

28-year-old female patient with NF-1. MRI was performed for pre-surgical planning. Coronal STIR (a) and axial T2W (b) images show poorly circumscribed, serpentine masses (asterisks) within the right orbital conal-extraconal and preseptal compartments. Findings are typical of an OPNF. There is associated dural ectasia of the right optic nerve sheath. Classic right-sided sphenoid wing dysplasia is also noted (arrow). The ADC map (c) shows no restriction of diffusion (ADC = 1.3 × 10⁻³ mm²/s) in keeping with the benign histology. d. Axial contrast-enhanced FS T1W image shows heterogeneous strong contrast enhancement of the OPNF (arrow). Axial (e) and sagittal (f) DTI 3D tractography views show complete disorganization of fibres within the OPNF surrounding the globe and optic nerve

Fig. 19

35-year-old female patient with left histologically proven orbital IOP. a. Axial T2W image shows a plaque-like hypointense extraconal lesion (arrowhead), adjacent to the lateral rectus muscle. Lymphoma was considered as an imaging differential. b. ADC map of the orbits of the same patient shows an ADC value of 1.1 × 10⁻³ mm²/s (arrowhead), which is higher than the ADC value expected for lymphoma. c. Axial PET/CT image of the same patient shows high FDG uptake within the lesion (arrow) (SUVmean = 5, SUVmax = 6) mimicking lymphoma

Fig. 20

50-year-old male patient with biopsy-proven IgG4-RD of the right orbit. Coronal bone-window CT image of the orbits (a) shows a well-circumscribed, extraconal, soft tissue-density mass located inferomedially in the right orbit. It is associated with bony erosion of the lamina papyracea (arrow). b. Axial T2W image of the same patient shows very low signal within the well-circumscribed lesion (arrow). Note that it is lower than usually seen in lymphoma. c. Axial contrast-enhanced FS TIW image shows homogeneous non-specific enhancement within the lesion (arrow). d. ADC map shows restricted diffusion (ADC = 0.9 × 10 ⁻³ mm²/s)

Fig. 21

Two different patients with orbital metastases. a – c. 74-year-old female patient with diplopia and a history of melanoma of the scalp 7 years previously. T2W (a), unenhanced FS T1W (b) and contrast-enhanced FS T1W (c) images of the orbits shows a conal-extraconal mass in the left orbit (arrows) and a second mass with similar imaging features in the suprazygomatic right masticator space (short arrows). The strongly hyperintense signal in b (arrows) suggests the presence of haemorrhage and/or melanin. Imaging findings are strongly suggestive of metastases from melanoma. Findings were confirmed by biopsy. d – f. 71-year-old female patient with known breast cancer. d. Axial CECT image shows a well-circumscribed enhancing mass in the left orbit in extraconal location (arrow). e. Coronal STIR image of the same patient shows non-specific moderately high signal of the metastatic deposit (thick arrow). Thin arrow points to the left optic nerve. f. Axial PET/CT image of the same patient shows physiological high FDG uptake in the extra-ocular muscles making it difficult to detect the metastatic lesion (arrow). As the imaging findings in this case are non-specific, the diagnosis of orbital metastasis can be suggested only when the clinical background is known. Biopsy confirmed metastasis from breast cancer

Fig. 22

60-year-old male patient with desmoplastic melanoma of the right eyelid. a. Axial T2W image shows a heterogeneous signal-intensity lesion involving the subcutaneous tissue of the right lateral canthus (big arrow) with an infiltrating component extending into the extraconal compartment of the right orbit. There is suspicious invasion of the muscle cone and the globe (short arrow). b: Axial T1W image of the same patient does not show hyperintense signal within the lesion in keeping with low melanin content. c. Coronal contrast-enhanced FS TIW image reveals avid enhancement within the lesion. d. Axial PET/CT image of the same patient shows high FDG uptake within the lesion due to high glucose metabolism. No other lesions were detected in the rest of the body