Cavernous venous malformations of the orbit, also known as cavernous haemangiomas, are the most common vascular lesion of the orbit in adults.
It is important to note that according to newer nomenclature (ISSVA classification of vascular anomalies) these lesions are merely known as slow flow venous malformations. Having said that, it is probably helpful in reports to include the word 'cavernous' as this term is ubiquitous in the literature and most familiar to many clinicians.
Cavernous malformations are found throughout the body. This article focuses on orbital cavernous haemangiomas. For a general discussion please refer to the general article on cavernous venous malformation.
Cavernous haemangiomas are the most common vascular lesions of the orbit in adults and accounting for 5-7% of all orbital tumours. However, debate exists about whether these lesions should actually be considered tumours 3. They usually present in middle age (30-50 years of age) and there appears to be a female predilection 2-3.
Clinical presentation is usually with a slowly growing orbital mass resulting in proptosis. Diplopia and visual field defects (from optic nerve compression) may also occur 3.
Cavernous haemangiomas are well-circumscribed masses bounded by a fibrous pseudocapsule, without prominent arterial supply (accounting for the relatively slow enhancement). They are composed of dilated large vascular spaces (thus cavernous) lined by flattened and attenuated endothelial cells 1,3.
As flow is slow, and vascular spaces large, areas of thrombosis are common 3-4.
Unlike the name 'haemangioma' suggests, these lesions may not be tumours as there is no cellular proliferation 3, but rather gradually enlarging vascular malformations and as such some authors prefer the term cavernous malformation.
In some cases prominent fibrosis is present, and these lesions are referred to by some authors as sclerosing haemangiomas 1.
Although cavernous haemangiomas can be located anywhere within the orbit (and for that matter pretty much anywhere in the body: see cavernous venous malformation article) over 80% are located within the intraconal compartment, most commonly in the lateral aspect 1-3.
They are usually round or oval in cross section and although frequently abut the globe, they do no deform it, but rather are deformed by the globe, on account of their soft consistency 1,3.
Large lesions may be associated with expansion of the bony confines of the orbit 3.
Ultrasound demonstrates a smoothly circumscribed retrobulbar lesion with regular moderate to high internal echogenicity 3-4. No flow can be demonstrated on Doppler scanning 4.
Cavernous haemangioma appears as a well circumscribed, rounded or oval soft tissue density mass when they are small and becomes deformed due to their soft nature when get larger; they are somewhat hypoattenuating compared to muscle which gradually and incompletely fills in following administration of contrast 1,2.
The orbital apex is usually spared 3.
Sclerosing haemangiomas sometimes demonstrate calcification 1.
Appearance on MRI is the same morphologically as on CT, with the following signal intensities:
- isointense compared to muscle
- if areas of thrombosis are present, then hyperintense regions may be visible 3
- hyperintense compared to muscle
- may have low-intensity septation
- pseudocapsule is of low intensity
- T1 C+ (Gd): slow gradual irregular enhancement with delayed wash out
Angiographically haemangiomas are occult as enhancement occurs only in a delayed fashion 2.
Treatment and prognosis
If the lesion is found incidentally and no exophthalmos or visual complications are present then conservative management is recommended, with periodic MRI imaging.
In cases where symptoms are present, or growth of the lesion is demonstrated on follow-up imaging, surgical removal is curative.
The differential depends on the location but is essentially that of orbital vascular lesions with the addition of a few non-vascular tumours.
For the more common intra-conal variety the differential includes 1-3:
- optic nerve meningioma
- orbital schwannoma
- sclerosing haemangioma (a variant rather than a distinct entity)
- orbital metastases
- orbital fibrous histiocytoma
- orbital lymphoma
- orbital venous varix
- capillary haemangioma of orbit
If extraconal the differential also includes 1-3:
- 1. Som PM, Curtin HD. Head and neck imaging. Mosby Inc. (2003) ISBN:0323009425. Read it at Google Books - Find it at Amazon
- 2. Lin E, Garg K, Escott E et-al. Practical differential diagnosis for CT and MRI. Thieme Medical Pub. (2008) ISBN:1588906558. Read it at Google Books - Find it at Amazon
- 3. Müller-Forell WS, Boltshauser E. Imaging of Orbital and Visual Pathway Pathology. Springer Verlag. (2005) ISBN:3540279881. Read it at Google Books - Find it at Amazon
- 4. Byrne SF, Green RL. Ultrasound of the eye and orbit. Mosby Inc. (2002) ISBN:0323012078. Read it at Google Books - Find it at Amazon
Vascular tumours and malformations
vascular malformations and tumours
- vascular tumours
- tufted angioma (with or without Kasabach Merritt syndrome)
- Kaposiform haemangioendothelioma (with or without Kasabach Merritt syndrome)
- spindle cell haemangioendothelioma
- other, rare hemangioendotheliomas
- dermatologic acquired vascular tumors
- slow flow vascular malformations
- capillary malformation (CM)
- venous malformation (VM)
- common sporadic venous malformation
cavernous venous malformation (cavernoma or cavernous haemangioma)
- cerebral cavernous venous malformation
- orbital cavernous venous malformation
- hepatic cavernous venous malformation (hepatic haemangioma)
- splenic cavernous venous malformation (splenic haemangioma)
- breast venous malformation (breast haemangioma)
- retroperitoneal venous malformation
- soft tissue venous malformation
- primary intraosseous venous malformation
- cardiac venous malformations
- cavernous venous malformation (cavernoma or cavernous haemangioma)
- Bean syndrome
- familial cutaneous and mucosal venous malformation
- glomuvenous malformation (glomangioma)
- Maffucci syndrome
- common sporadic venous malformation
- lymphatic malformation (LM)
- fast flow vascular malformations
- arterial malformation
- arterial malformation
- arteriovenous fistulae (with one or more shunts)
- arteriovenous malformations (with a nidus of multiple shunts)