- 1.
Should all orbital capillary hemangiomas be excised?
No. Orbital capillary hemangioma (hemangioma of infancy) should be treated only if there is evidence of:
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Amblyopia caused by refractive error (induced myopia or astigmatism) or
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Ptosis causing visual obstruction or head tilt.
Treatment options include the following:
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The treatment of choice at present is the use of systemic β-blockers (propranolol). Systemic monitoring should be performed during induction to ensure cardiopulmonary stability. The use of topical therapy for more superficial lesions is under investigation, with positive initial results. However, the efficacy of topical therapy for deeper orbital lesions has not yet been proven.
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Corticosteroid injections or systemic therapy. Of note, corticosteroid suspensions (e.g., triamcinolone) may rarely case vascular occlusions and visual loss when injected into the orbit. Such medications now come with a black-box warning from the manufacturer warning against their use in the periocular region. The clinician should either obtain a clear consent from the parents or guardians or use a nonsuspension corticosteroid injection or systemic therapy.
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Excision is usually reserved for cases unresponsive to more conservative therapy.
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Interferon α-2 therapy, especially in large localized or systemic cases. This option is becoming more of a rarity with the advent of β-blocker therapy. Interferon α-2 therapy in children is also associated with a risk of spastic diplegia.
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- 2.
What orbital tumors can mimic orbital cellulitis?
In both adults and children, the differential includes noninfectious inflammation (idiopathic orbital inflammatory syndrome (inflammatory orbital pseudotumor), sarcoidosis, thyroid eye disease (Graves’ orbitopathy), and granulomatosis with polyangiitis (Wegener granulomatosis)).
In children, also consider:
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Ruptured dermoid cyst. This causes a fulminant soft tissue inflammation.
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Rhabdomyosarcoma. Usually, this is painless.
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Lymphangioma, especially with rapid expansion from a blood-filled “chocolate cyst.”
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Neuroblastoma. This can present with a rapid onset of proptosis and ecchymosis.
In adults, also consider:
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Ruptured dermoid cyst.
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Lymphangioma.
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Extrascleral spread and/or necrosis of an intraocular melanoma.
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Metastatic disease to the orbit.
- •
- 3.
What are the most common causes of childhood proptosis?
- •
Orbital cellulitis
- •
Capillary hemangioma (hemangioma of infancy)
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Idiopathic orbital inflammatory syndrome (inflammatory orbital pseudotumor)
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Dermoid cyst
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Rhabdomyosarcoma
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Lymphangioma
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- 4.
When and how does cavernous hemangioma usually present?
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Cavernous hemangioma is the most common vascular orbital tumor in adults and the most common benign orbital tumor.
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Typically presents in the 4th and 5th decades.
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Well-circumscribed on imaging (see question [CR] ).
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It is not the adult equivalent of capillary hemangioma. Not only are the lesions distinct histopathologically, but cavernous hemangioma is a slowly proliferating entity.
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Because of its slow growth, it is usually a well-tolerated lesion, causing few symptoms. Visual loss, if any, is slow and limited to lesions of the orbital apex.
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Excision is curative.
- •
- 5.
List some basic facts about fibrous histiocytoma and hemangiopericytoma.
- •
Fibrous histiocytoma, malignant fibrous histiocytoma, and hemangiopericytoma have been characterized as subtypes of solitary fibrous tumor. Because all of these entities are spindle-cell tumors, histopathologic diagnosis may be difficult.
Fibrous histiocytoma:
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Fibrous histiocytoma is the most common mesenchymal tumor of adults.
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Excision is curative.
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Malignant transformation is rare, but possible.
Hemangiopericytoma:
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A tumor of pericytes.
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Histopathologic appearance has little correlation with clinical behavior. In other words, a histologically benign lesion may behave aggressively and recur after excision, whereas a tumor with aggressive features on microscopic examination may never recur.
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Patients need to be followed clinically even after excision for possible recurrence or aggressive behavior.
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- 6.
What about orbital schwannoma?
- •
A tumor of the Schwann cells, which form the lining of peripheral nerves.
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Schwannomas typically arise from sensory nerves, although motor and parasympathetic nerve involvement within the orbit has also been reported.
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N.B. Schwannomas do not arise from the optic nerve sheath (the optic nerve is lined with meninges; a tumor arising from the optic nerve sheath is a meningioma, not a schwannoma.
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Within the orbit, most schwannomas arise from sensory nerve sheaths, which may explain their predilection for the superior orbit.
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The Antoni A and B patterns are the classic histologic findings in schwannoma. The A pattern is characterized by abundant, tightly packed spindle cells, whereas the B pattern exhibits fewer cells within a myxoid matrix.
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- 7.
How does one order an orbital computed tomography (CT) scan?
- •
Order axial and coronal cuts in all cases. The newest multiscan CTs typically image in the axial plane only and are then reconstructed as coronal and parasagittal images without loss of resolution or need for patient repositioning.
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If direct coronals cannot be obtained, coronal reconstructions usually suffice, but this is really an issue only with older scanners.
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Always review both soft tissue and bone windows.
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Never order cuts greater than 3 mm.
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Intravenous contrast is helpful in cases of infection or inflammation. It is not necessary for trauma or thyroid eye disease.
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In deep orbital and skull base processes, consider ordering the scan with intraoperative guidance protocols. This will allow a more precise localization of anatomy if subsequent intraoperative image guidance is needed during surgery.
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- 8.
How does one order an orbital magnetic resonance image (MRI)?
Very carefully.
The Rules of Orbital MRI
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NEVER order MRI as the first imaging modality in trauma, for unresponsive patients, or for poor historians. Occult metal within the magnetic field can move and cause severe soft tissue damage.
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Always order axial, coronal, and parasagittal views.
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Always include the cavernous sinus and paranasal sinuses.
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Always order gadolinium and fat suppression ( Fig. 52-1 ). Be careful ordering gadolinium in patients with known or suspected renal disease, as this may result in nephrogenic systemic fibrosis.
Figure 52-1
A and B, T1-weighted magnetic resonance images of the orbit with fat suppression.
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In T1, orbital fat is bright and vitreous is dark.
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In T2, vitreous is brighter than fat.
- •
The majority of orbital masses are dark in T1 before gadolinium administration.
Exceptions to this rule are:
- 1.
Lesions containing melanin (e.g., melanoma);
- 2.
Lesions containing fat (e.g., lipoma, liposarcoma);
- 3.
Lesions containing mucus (mucocele, dermoid cyst);
- 4.
Subacute blood (2 to 7 days old).
- 1.
- •
- 9.
Discuss the histologic classification of orbital rhabdomyosarcoma.
Orbital rhabdomyosarcoma (RMS) is histologically divided into three main groups (other schema are sometimes used, but this is the most basic):
- 1.
Embryonal
- 2.
Alveolar
- 3.
Pleomorphic
The average age of onset is 9 years, but the span is broad. RMS is thought to arise from pleuripotential mesenchymal tissue within the orbit and not from extraocular muscle. Useful facts to remember about each group follow:
- 1.
Embryonal
- •
Further subdivided into classic, botryoid, spindle cell, and anaplastic
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Most common histology in children
- •
The botryoid subtype is defined as an embryonal RMS abutting a mucosal surface (e.g., conjunctiva)
- •
- 2.
Alveolar
- •
Appears to affect the inferior orbit most frequently and carries the worst prognosis
- •
Fortunately, recent findings by the Intergroup Rhabdomyosarcoma Study (IRS) indicate that with more aggressive therapy, the prognosis for alveolar RMS approaches the prognosis for the embryonal form
- •
- 3.
Pleomorphic
- •
Occurs in older adults
- •
- 1.
- 10.
How is orbital RMS best treated? What is the prognosis?
- •
Much of what is known about the treatment of orbital rhabdomyosarcoma comes from the four IRSs.
- •
Treatment of orbital RMS consists of a combination of chemotherapy and radiation therapy.
- •
Radiation therapy in doses of 40 to 60 Gy definitely carries significant morbidity for the globe, but the IRS-III concluded that it is still necessary for adequate treatment. Lower doses of radiation are currently under study.
- •
Orbital and genitourinary RMS carry the best prognosis for unclear reasons.
- •
Local spread from the orbit into the paranasal sinuses or cranial vault decreases survival rates.
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- 11.
With regard to lacrimal gland lesions, what is the “rule of 50s”?
The rule of 50s summarizes the incidence of lacrimal gland tumors in an orbital referral practice:
- •
50% of lacrimal gland lesions are nonepithelioid, consisting mostly of inflammatory and lymphoproliferative lesions, and 50% are of epithelial origin.
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50% of the epithelial tumors are benign pleomorphic adenomas (benign mixed tumor) and 50% are various malignant types.
- •
50% of the malignant tumors are adenoid cystic carcinomas.
- •
50% of the adenoid cystic carcinomas are of the basaloid variant. The final rule is important clinically, because a basaloid histopathology for adenoid cystic carcinoma carries the worst prognosis.
- •
- •
- •
In a general ophthalmology practice the rule of 50s does not apply. The incidence of infectious and noninfectious inflammatory dacryoadenitis is several times higher than in an orbital referral practice.
- •
- 12.
What factors help to distinguish benign and malignant epithelial lacrimal gland tumors?
See Table 52-1 .
