Orbital inflammatory pseudotumour

Suspected
idiopathic sclerosing orbital inflammation presenting as immunoglobulin G4-related disease: a case report. Patient presented with swelling and ptosis of the right upper eyelid. (a) Head CT of the orbit revealed abnormal high density area (yellow circle); (b) MRI revealed the presence of an infiltration of the right intraorbital diffuse mass which regressed and decreased in size one month after treatment was initiated.
jmedicalcasereports.biomedcentral.com • CC-by-2.0
Value of
diffusion-weighted magnetic resonance imaging (DWI) in differentiating orbital lymphoma from idiopathic orbital inflammatory pseudotumor. A 34-year-old male patient with acute onset of right-sided dull aching orbital pain and limited orbital movement Coronal T2WI and T1WI images A, B show enlarged right inferior and lateral recti muscles displaying T1 and T2 isointense signal with minor similar changes involving the left inferior rectus muscle. Complementary non-enhanced CT coronal image C shows bulky right inferior muscle and to lesser extent right lateral rectus muscle. Contrast-enhanced sagittal T1 fat-saturated image D shows marked contrast enhancement of inferior rectus muscle bulk. No diffusion-weighted restriction seen on DWI (b500) (E) and ADC (F). The ADC value is 1.1 × 10−3 mm2/sec. Right-sided orbital inflammatory pseudotumor, Myositic type; responded well 2 weeks after therapeutic trial with corticosteroids
ejrnm.springeropen.com • CC-by-4.0
Value of
diffusion-weighted magnetic resonance imaging (DWI) in differentiating orbital lymphoma from idiopathic orbital inflammatory pseudotumor. A 23-year-old male patient with acute rhino-sinusitis presented with left-sided orbital pain, mild proptosis and limited orbital gaze. Coronal T1 A shows diffusely enlarged left superior, medial and lateral recti with mild stranding of the left retrobulbar fat. Coronal and sagittal T1 fat-sat post-contrast images B, C show homogeneous enhancement of these left orbital muscles. Axial non-contrast CT image bone window D reveals ethmoidal and sphenoidal mild sinusitis. No diffusion-weighted restriction seen on DWI (b500) E and ADC F. The ADC value is 1.05 × 10−3 mm2/sec. Left-sided orbital inflammatory pseudotumor, Myositic type; responded well 2 weeks after therapeutic trial with corticosteroids
ejrnm.springeropen.com • CC-by-4.0
Value of
diffusion-weighted magnetic resonance imaging (DWI) in differentiating orbital lymphoma from idiopathic orbital inflammatory pseudotumor. A 35-year-old female patient with acute rhino-sinusitis presented with left-sided orbital pain, mild proptosis and limited orbital movement. Axial T1- and T2-weighted images of the left orbit A, B show a primarily extraconal mass involving the left medial rectus muscle with intraconal extension. No diffusion-weighted restriction seen on DWI (b500) image (C) and ADC (D). The ADC value for the mass is 1.09 × 10−3 mm2/s. Histopathologically proved left-sided orbital inflammatory pseudotumor by FNAC
ejrnm.springeropen.com • CC-by-4.0
Value of
diffusion-weighted magnetic resonance imaging (DWI) in differentiating orbital lymphoma from idiopathic orbital inflammatory pseudotumor. A 13-year-old male with acute pan-sinusitis; presented with right-sided dull aching orbital pain, mild proptosis and limited orbital gaze. Axial T1 image (A) shows diffusely enlarged right superior and medial recti with mild haziness of the right intraconal retro bulbar fat. Axial T2 image (B) shows diffuse enlargement of the right superior and medial recti muscles with mild hyperintense signal. No diffusion weighted restriction seen on DWI (b500) image (C) and ADC (D). The ADC value is 1.34 × 10−3 mm2/sec. Right-sided orbital inflammatory pseudotumor, Myositic type. Therapeutic trial with corticosteroids was done and the patient relieved after 5 weeks
ejrnm.springeropen.com • CC-by-4.0
Value of
diffusion-weighted magnetic resonance imaging (DWI) in differentiating orbital lymphoma from idiopathic orbital inflammatory pseudotumor. A 56-year-old male with acute sinusitis presented with left-sided orbital pain and blurring of vision. Axial T1-weighted image A shows hypointense signal involving the sclera of left eye, the related intra- and extraconal fat planes and the lateral rectus muscle. Coronal T2-weighted image B shows an extraconal mass involving the left lateral rectus muscle, the lacrimal gland with intraconal extension. Post-contrast T1 fat-saturated images C,D show homogeneous enhancement of the extraconal mass and its intraconal component. No diffusion-weighted restriction seen on DWI (b500) (E) and ADC (F). The ADC value for the lesion is 1.27 × 10 −3 mm2/ sec. FNAC of the mass proved to be left-sided orbital inflammatory pseudotumor
ejrnm.springeropen.com • CC-by-4.0
Idiopathic
orbital inflammation • Idiopathic orbital inflammation - Ganzer Fall bei Radiopaedia
Guan H, Idiopathic orbital inflammation. Case study, Radiopaedia.org (Accessed on 22 Jan 2023) https://doi.org/10.53347/rID-160369 • CC by-nc-sa 3.0 (modified)
Idiopathic
orbital inflammation • Myositic orbital pseudotumor - inferior rectus muscle - Ganzer Fall bei Radiopaedia
Haouimi, A. Myositic orbital pseudotumor - inferior rectus muscle. Case study, Radiopaedia.org. (accessed on 21 Oct 2022) https://doi.org/10.53347/rID-79130 • CC by-nc-sa 3.0 (modified)
Bilateral
idiopathic orbital pseudotumour in a child: a case report. Magnetic resonance imaging. Orbital magnetic resonance imaging showed myositis, slight signal enhancement of both extraocular muscles on axial T2-weighted magnetic resonance imaging without significant change for optic nerve; soft tissue swelling and retinal detachment of the left eye. No other significant abnormality was seen in MRI of brain
bmcophthalmol.biomedcentral.com • CC-by-4.0
Differentiation
of orbital lymphoma and idiopathic orbital inflammatory pseudotumor: combined diagnostic value of conventional MRI and histogram analysis of ADC maps. A female patient with idiopathic orbital inflammatory pseudotumor. Axial fat-saturated T2W image a shows a well-defined isointense mass in lacrimal fossa. Axial contrast enhanced T1W image b demonstrates significant enhancement, similar to that of extraocular muscles. Pixel-by-pixel colored ADC map c was obtained and then embedded with the axial DWI. The corresponding ADC histogram from VOI d a relatively flat peak and a slight tail on the right. Whole-tumor ADCmean was 0.730 × 10− 3 mm2/s, ADC10 was 0.590 × 10− 3 mm2/s, skewness was 0.73, and kurtosis was 0.80
bmcmedimaging.biomedcentral.com • CC-by-4.0
Teenager with
acute onset of left orbital pain. Axial (left) and coronal (right) CT with contrast of the orbits shows diffuse thickening of the muscle belly of the left lateral rectus muscle. No other inflammatory changes were seen in the orbits.The diagnosis was idiopathic orbital inflammation.
pediatricimaging.org • CC-by-nc-sa 4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Idiopathic orbital inflammation (IOI), also known as orbital pseudotumor and non-specific orbital inflammation, is an idiopathic inflammatory condition that most commonly involves the extraocular muscles. Less commonly there is inflammatory change involving the uvea, sclera, lacrimal gland, and retrobulbar soft tissue.

The exact etiology is not known but an association with many inflammatory/autoimmune diseases is reported.

Terminology

Many terms are used interchangeably in the literature to refer to idiopathic orbital inflammation including orbital pseudotumor, non-specific orbital inflammation and orbital inflammatory syndrome.

Clinical presentation

Patients typically present with rapid-onset, usually unilateral (~90% of cases), painful proptosis and diplopia. Idiopathic orbital inflammation is a diagnosis of exclusion; atypical presentation, poor response to treatment with corticosteroid and recurrence should prompt biopsy to exclude other diseases.

Pathology

Histologically acute lesions demonstrate lymphocytes (which can be mistaken for orbital lymphoma), plasma cells, and giant cell infiltration.

Classification

Division into a number of subgroups according to location has been proposed:

  • lacrimal pseudotumor (dacryoadenitis)
  • anterior pseudotumor: in the fat immediately behind the globe
  • posterior pseudotumor: in the fat at the orbital apex; distinguished from Tolosa-Hunt syndrome in that the cavernous sinus is spared
  • myositic pseudotumor (myositis): predominantly involve the EOMs and therefore mimic thyroid-associated orbitopathy (TAO) but unlike TAO it also involves the tendons
  • optic perineuritis: involvement of the optic nerve sheath
  • diffuse pseudotumor: affecting multiple compartments
    • Associations

    The condition has been associated with other inflammatory and autoimmune conditions:

    Radiographic features

    Imaging demonstrates enlargement of the muscle belly of one (or more) extraocular muscles typically with the involvement of their tendinous insertions. Involvement of the tendinous insertion distinguishes it from thyroid-associated orbitopathy (TAO) in which the insertion point is spared. However, sparing of the anterior tendon does not preclude the diagnosis of idiopathic orbital myositis .

    Additional inflammation can be seen in surrounding tissues, including the orbital fat, lacrimal gland, and optic nerve sheath.

    It can appear as an infiltrative mass and extends outside of the orbit via superior or inferior orbital fissures. Extension into the cavernous sinus, meninges, and dura can occur. It is most commonly unilateral but can be bilateral in 25% of cases.

    MRI

    Reported signal characteristics include:

    • T1: affected region typically isointense (to extra-ocular muscles)  but can also be hypointense
    • T2: affected region typically hypointense due to fibrosis and with more progression of fibrosis it becomes more hypointense, but the signal can also be iso- to hyperintense to extra-ocular muscles
    • T1 C+ (Gd): moderate to a marked diffuse enhancement 

    Treatment and prognosis

    Most cases resolve rapidly with treatment (usually corticosteroids suffice) although in a subset with more chronic progression chemotherapy and radiotherapy may be required. A degree of residual fibrosis can be demonstrated, especially in the more refractory cases.

    History and etymology

    The disease was first described by Birch-Hirschfeld et al. in 1905 . They also introduced the term orbital pseudotumor afterward in 1930 .

    Differential diagnosis

    One of the main differential diagnoses of idiopathic orbital inflammation is orbital lymphoma. There is considerable overlap between these entities both clinically and radiologically. However, orbital lymphoma usually presents as a progressive orbitopathy rather than acutely, is more often bilateral, shows lower values on ADC, and does not respond to corticosteroid.

    Other imaging differential considerations include:

    Siehe auch:
    und weiter:
    Assoziationen und Differentialdiagnosen zu inflammatorischer Pseudotumor der Orbita:
    Unterscheidung
    inflammatorischer Pseudotumor der Orbita und orbitales Lymphom
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    Sarkoidose
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    Polyarteriitis
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    sclerosing
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    fibrosierende
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    inflammatorischer
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    pediatricimaging.org • CC-by-nc-sa 4.0
    Rheumatoide
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    orbitales
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    Granulomatose
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    Dermatomyositis
     
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