Orbital cavernous hemangioma is a benign, slowly progressive vascular neoplasm of endothelial-lined spaces surrounded by a fibrous capsule. It most commonly presents in middle-aged adults (ages 20-40 years) and women are affected more than men.
Its location is most often within the muscle cone, lateral to the optic nerve. Treatment is usually reserved for symptomatic patients (diplopia or visual disturbance) and includes surgical excision.
Cavernous hemangioma is the most common benign neoplasm of the orbit. It is considered a congenital abnormality. There is no evidence to suggest a heritance pattern. It is not a neoplasm in the usual sense, as it is not derived from a single cell, proliferating cell.
Instead, cavernous hemangiomas are composed of a network of vascular channels separated by fibrous tissue stroma. Growth of the tumor is secondary to budding of vascular channels into surrounding tissue.
Orbital cavernous angiomas can increase intraorbital volume with a resultant mass effect. Although cavernous hemangiomas are histologically benign, they can encroach on intraorbital or adjacent structures and can be considered anatomically or positionally malignant.
Visual acuity or field compromise, diplopia, and extraocular muscle or pupillary dysfunction can result from compression of intraorbital contents by the angioma. Lagophthalmos can result in exposure keratopathy, keratitis, and corneal perforation.
There are no established risk factors for cavernous hemangioma. However, pregnancy has been associated with accelerated growth of pre-existing cavernous hemangiomas.
Cavernous hemangioma is an encapsulated nodular mass composed of dilated, cavernous vascular spaces separated by connective tissue stroma. Flattened endothelial cells line the vascular spaces, which are filled with blood.
One to five layers of smooth muscle cells surround the vascular spaces. These histopathologic features may also be seen in lymphangioma.
Cavernous hemangioma is a congenital abnormality that presents after sufficient growth causes cosmetic or visual disturbance. Growth of the tumor is a result of budding of the vascular channels into the surrounding soft tissue.
It has been speculated that a localized, low-grade change in hemodynamics causes opening of new channels allowing for extension of the tumor into the surrounding interstitium. A fibrous capsule forms at the interface of the advancing tumor and the normal neighboring tissue.
Surrounding soft tissue is displaced, compressed or occasionally incorporated into the tumor. Symptomatic visual impairment occurs as a result of involvement of the optic nerve, extraocular muscles or surrounding vasculature.
Cavernous hemangioma is a congenital vascular neoplasm. There is no primary prevention for this disease entity
The diagnosis of cavernous hemangioma is suspected clinically and confirmed with orbital imaging, most commonly MRI. They most commonly present as solitary, unilateral lesions.
However, multiple tumors have been reported, particularly in Blue Rubber Bleb Nevus Syndrome. Rarely, they may present simultaneously with a cavernous hemangioma of the brain.
Cavernous hemangiomas have also been reported to present as an osseous lesion involving the orbital bones or as a tumor within the lacrimal gland.
The classic history for cavernous hemangioma is an adult, more often a women, in the 2nd to 6th decade of life with slowly progressive, painless proptosis. Patients usually report a gradual onset of symptoms over a period of 6 months to 2 years.
Induced hyperopia or optic nerve compression may result in a complaint of decreased vision. Diplopia may also be a feature of the patient’s history due to extraocular muscle restriction. Gaze evoked amaurosis has been reported.
Depending on the size and location of the cavernous hemangioma, exam findings may range from normal to severe axial proptosis with poor vision, elevated intraocular pressure (IOP), motility defects and a relative afferent pupillary defect.
Physical exam should include assessment of visual acuity, pupillary reaction, Hertel exophthalmometry, intraocular pressure, slit lamp exam with fluorescein and dilated fundus exam.
A tumor of sufficient size may induce hyperopia or compress the optic nerve causing decreased visual acuity or an afferent pupillary defect.
Hertel exophthalmometry will enable the examiner to appreciate small amounts of proptosis. Slit lamp exam with fluorescein instillation should be used to assess for surface irregularities that may occur as a result of incomplete lid closure from proptosis.
Dilated fundus exam may reveal optic nerve swelling, choroidal folds or circumscribed compression of the globe.
The most common signs of cavernous hemangioma include axial proptosis, motility defects and optic nerve swelling. It does not usually produce inflammatory signs.
Patients with cavernous hemangiomas usually present with painless, progressive proptosis. As the tumor grows and involves the extraocular muscles, optic nerve and globe, patients will report double vision and decreased vision.
The diagnosis of cavernous hemangioma may be suspected clinically but is confirmed with orbital imaging. A presenting complaint of proptosis should always prompt a consideration of orbital imaging.
Pupillary abnormalities elevated IOP, optic nerve swelling and choroidal folds should raise suspicion of a possible orbital mass.
Orbital imaging with B-scan, A-scan, computed tomography (CT) and magnetic resonance imaging (MRI) all contribute to the diagnosis of cavernous hemangioma. B-scan ultrasound reveals a smooth, round to oval lesion behind or apposing the globe with moderate to strong sound attenuation.
A scan ultrasound exhibits a regular internal structure, high internal reflectivity and moderate to strong sound attenuation. On CT scan, cavernous hemangioma appears as a well circumscribed, homogenous mass slightly hyperdense to muscle, located intraconally.
In long-standing lesions, bone remodeling and small foci of calcification may occur. Low vascular flow results in mild contrast enhancement. Coronal imaging is especially important to assess for position of the tumor relative to the optic nerve.
MRI T1-weighted images of cavernous hemangioma exhibit a homogenous signal, isointense to muscle and gray matter, hypointense to fat. T2-weighted images produce a signal hyperintense to fat and brain.
Gadolinium enhancement results in an initial central patch of enhancement with later total homogenous enhancement.
Cavernous hemangioma is diagnosed radiologically after a thorough clinical assessment.
The differential diagnosis for a well circumscribed, round to oval, solid orbital mass includes: peripheral nerve sheath tumors (schwannoma and neurofibroma), hemangiopericytoma, fibrous histiocytoma, solitary fibrous tumor and melanoma.
Management of cavernous hemangioma is dependent on the presence or absence of symptoms. For small, asymptomatic lesions, periodic observation with once or twice yearly pupil exams, visual acuity, color vision, exophthalmometry, dilated fundoscopy, visual fields and CT or MRI studies is appropriate.
For larger lesions causing diplopia or visual disturbances, surgical excision is the treatment of choice. There is no current role for radiotherapy.
As with any examination, a thorough history and review of symptoms is paramount in formulating a comprehensive list of differential diagnoses.
Examination of patients should commence with an observation of facial features, noting any asymmetry or scarring.
Palpation of the lids and globes allows one to assess differences in lid fullness and increased resistance to retropulsion. Hertel exophthalmometry can detect axial proptosis and should be documented for comparison on follow-up visits.
- Visual and color acuities, as well as visual fields, should be assessed, followed by testing of pupillary and extraocular muscle function.
- Decreased color vision, visual field deficits, and relative afferent pupillary defects warrant immediate imaging to rule out a compressive optic neuropathy.
Additionally, any extraocular motility disturbance should be quantitated with prismatic measurements.
Rarely, slit lamp or penlight evaluation may find dilated and tortuous epibulbar vessels, an epibulbar cherry-red spot, or a darkening over insertions of extraocular muscles.
Dilated funduscopic examination may elucidate choroidal folds secondary to compression of the globe by the mass. If the tumefaction is in close proximity to the optic nerve, visible changes may include edema, elevation, pallor, and even atrophy in severe cases.
Treatment of cavernous hemangioma is via surgical excision. There are currently no medical therapies for the treatment of cavernous hemangioma.
The choice of approach to surgical excision of a cavernous hemangioma depends on the location and size of the tumor. Cavernous hemangiomas involving the anterior two-thirds of the orbit can be resected via an anterior eyelid, transconjunctival or transcaruncular approach. More posteriorly located tumors may require a lateral orbitotomy.
A transcranial approach may be required for lesions involving the orbital apex. A cryoprobe is often used to aid in removal with minimal blood loss. Even large tumors are usually removed easily and completely.
Surgical follow up
Follow-up is similar to that after any orbital surgery. The patient is usually seen in the first week after surgery and then at 1 month. The surgeon should monitor the patient for recurrences if the tumor was incompletely excised.
Visual loss from injury to the central retinal artery has been reported as a complication of surgery. Blood loss is typically minimal due to the tumors encapsulation. As with any orbital surgery, there is always the risk of injury to extraocular muscles, optic nerve and surrounding adnexal structures.
With complete exicision of the cavernous hemangioma, the visual prognosis is excellent. If the tumor is incompletely excised, recurrences may occur and in some cases are relentless. Hyperopia as a result of mass effect against the posterior globe may persist even after tumor excision.