Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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August 20, 2020
Tolosa-Hunt Syndrome
- Background:
- Orbital pseudotumor is an inflammatory process of the orbit without known systemic or local cause. It is posited to be immune-mediated, with infiltration by multiple chronic inflammatory cells.
- Tolosa-Hunt syndrome (TH) is a variant of the disease with involvement of the orbital apex and extension into the cavernous sinus.
- Cavernous sinus inflammation is the defining characteristic of TH, as some cases demonstrate it is not necessary to have adjacent orbital involvement. The inflammation that is seen in TH causes mass effect on the cranial nerves within the cavernous sinus, leading to episodic orbital pain that may progress to cranial nerve paresis.
- Other variants of orbital pseudotumor include sclerosing orbital pseudotumor, which is defined by the presence of fibrosis, as well as the IgG4-related variant, which consists of specifically plasma cell–mediated inflammation.
- Clinical Presentation:
- Symptoms relapse and remit with time and include gnawing pain behind the affected eye, typically unilateral, that progresses to ophthalmoplegia and cranial nerve paresis.
- Symptoms can present at any age.
- There is an equal male and female predilection.
- Key Diagnostic Features:
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Unilateral T2-hyperintense mass expanding the cavernous sinus; of note, sclerosing or IgG4-related variants of this disorder have a lower T2 signal due to fibrosis.
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Moderate to intense enhancement
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± Involvement of the superior orbital fissure and narrowing of the cavernous internal carotid artery
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Findings often resolve only to reemerge later in time.
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- Differential Diagnoses: TH is a diagnosis of exclusion. Other causes of cavernous sinus mass lesion must be excluded:
- Meningioma: T1- and T2-isointense mass; may restrict diffusion; avid enhancement ± dural tail; dense on CT; regional hyperostosis
- Lymphoma: T2 hypointense; restricts diffusion; homogeneous enhancement
- Schwannoma: T2-hyperintense mass; round or dumbbell-shaped; extends into Meckel cave; homogeneous enhancement; ± cysts when large
- Pituitary adenoma: Heterogeneously enhancing mass expanding the sella, extending into the cavernous sinus
- Neurosarcoid: Enhancement may be leptomeningeal, pachymeningeal, or nodular along CNs; involvement of pituitary/hypothalamus; abnormal CXR
- Tuberculosis: Enhancing basal meningitis; ± tuberculoma (T2-hypointense, enhancing parenchymal lesion); ± abscess; history of pulmonary TB
- Perineural spread of tumor: Widening of neural foramina; loss of perineural fat; enlargement and nodular enhancement of involved nerves
- Cavernous carotid fistula: Usual trauma history; enlarged superior ophthalmic vein; enlarged cavernous sinus; early filling of cavernous sinus on angiography
- Aneurysm: Circular lesion contiguous with cavernous ICA; may be patent (with flow void and pulsation artifact) or thrombosed
- Treatment:
- Mainstay is IV glucocorticoids.
- Specific regimens vary, but in general include initial high-dose glucocorticoids followed by a gradual taper over a period of 4–6 weeks.
- Spontaneous resolution without treatment is rare.
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