What is an orbital pseudotumor?
An orbital pseudotumor is a benign mass located in the tissue behind the eye. This area is called the orbit and is the part of the skull that holds the eye in place. In some cases, an orbital pseudotumor can occur in the periorbital portion (the area around the eye). Orbital pseudotumors are very rare.
A pseudotumor of the orbit can resemble cancerous tumors behind the eye. However, they are not a cancer, not infectious and do not spread to other parts of the body. Even though orbital pseudotumors don’t spread, the inflammation can affect structures located near the eye.
There are several other names for orbital pseudotumor, including:
- Orbital inflammatory pseudotumor (OIP)
- Idiopathic orbital inflammation (IOI)
- Nonspecific orbital inflammation (NSOI)
The condition can be mild or severe. It mainly occurs in young women, but it can affect anyone at any age.
Mild orbital pseudotumors may resolve on their own. Other cases may require corticosteroid therapy, radiation or surgery.
Orbital pseudotumor is not to be confused with pseudotumor cerebri, which involves fluid pressure building up in the brain and the optic nerve (the nerve that connects the eye to brain). Although pseudotumor cerebri can affect the eyes by causing swelling of the optic nerve, it is different.
Symptoms
Symptoms of orbital pseudotumor can range from mild to severe. Noted symptoms of the condition include:
- Eye swelling
- Protopsis (bulging eyes)
- Eye pain that can be extreme
- Double vision
- Decreased vision
- Difficulty moving the eyes
- Red eye (this is a less common symptom)
These signs and symptoms are carefully examined by a specialist eye doctor, typically:
- An ocular oncologist – A doctor who specializes in eye cancer
- A neuro-ophthalmologist – A doctor who specializes in the interactions between the brain and the eyes
- An oculoplastic specialist – A doctor who specializes in the structures that surround the eyes
If the doctor suspects that an orbital pseudotumor is present, an ultrasound or CT scan and biopsy can be performed for confirmation.
Diagnosis
Several types of tests may be performed to diagnose a pseudotumor of the orbit. Some of these tests include:
- X-ray of the skull
- MRI of the head
- CT scan of the head
- Ultrasound of the head
- Biopsy
Testing and scans are very important because orbital pseudotumors can be mistaken for other conditions. Conditions that may appear similar to an orbital pseudotumor include:
- Orbital cellulitis
- Thyroid eye disease
- A cancerous tumor
Orbital pseudotumor is diagnosed after excluding these other conditions.
Causes
The cause of orbital pseudotumor is unknown. Researchers believe there may be a correlation between the condition and the contraction of a staph infection or Lyme disease. It’s also thought that immune-mediated diseases may be connected to orbital pseudotumor.
Other conditions that may be associated with orbital inflammation include:
- Crohn’s disease
- Rheumatoid arthritis
- Ulcerative colitis
- Lupus
- Giant cell arteritis
- Multifocal fibrosclerosis
- Granulomatosis with polyangiitis (Wegener’s)
Complications
Orbital pseudotumors can put a large amount of pressure on the eyes, potentially causing damage to surrounding tissue.
The eyeball can be pushed far enough forward by a pseudotumor that the eyelids can no longer cover or protect the cornea (the outer clear layer of the eye). Without this protection, the eye can become very dry and may lead to scarring and even corneal ulcers.
Pressure from orbital pseudotumors can also affect the eye muscles. Movement may be limited for the muscles, interfering with the eyes’ ability to coordinate. This can lead to double vision and restricted eye movement.
Without proper treatment (or if unresponsive to therapy), an orbital pseudotumor can lead to vision loss. Inflammation can also spread to nearby structures, and critical cases can lead to secondary angle-closure glaucoma.
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Treatment
In mild cases, orbital pseudotumors sometimes resolve on their own. Some patients may be given systemic corticosteroids to reduce inflammation. Others may be referred for radiation therapy if corticosteroids are not effective.
If the orbital pseudotumor is severe, surgery may be recommended. During the procedure, the bones and fat in the orbit may be adjusted to relieve pressure on the eyeball.
In some circumstances, orbital pseudotumors need to be removed. A minimally invasive procedure called the endoscopic endonasal approach allows doctors to remove the mass through the nasal cavity without making any incisions. The orbital pseudotumor can be accessed and removed directly through the nasal passageway.
When to see a doctor
Contact your eye doctor if you experience the following symptoms. They can have many potential causes, including orbital pseudotumor:
- Ocular pain
- Redness
- Irritation
- Decreased or double vision
Your doctor will discuss testing, diagnosis and treatment options with you if they believe you may have an orbital pseudotumor. Since this condition can damage the eyes, suspicion of orbital pseudotumor generally means you will be referred to a specialist.
Be sure to schedule annual comprehensive eye exams as well. Your eye doctor will evaluate your vision and eye health to help keep your sight and eyes healthy over time.
