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ORBITAL PSEDOTUMOR
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Radiology Cases in Pediatric Emergency Medicine
Volume 6, Case 10 Martin I. Herman, MD
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Case |
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This is a 2 year old male who presents with a chief complaint of bilateral eye swelling. He had some swelling noted 2 weeks prior to this admission and was treated with antibiotics for a presumed sinusitis. The swelling did improve to some degree; however it never completely resolved. Over the past 2 weeks the swelling has worsened. There has been some itching but no fever. His vision is unaffected as far as his mother could tell. Diphenhydramine and erythromycin ophthalmic ointment were started and once again the swelling improved. They present today because the swelling is again worse. Mom denied any trauma to the lids or orbit, no eye discharge, and only mild redness. There are no symptoms to suggest hyperthyroidism.
His past medical history is negative for any diseases of the eyes, severe allergies, renal or cardiac disease, or thyroid dysfunction. His family history is unremarkable
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Examination
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He is a healthy appearing male who has mild proptosis of both eyes. There is mild conjunctival erythema but no discharge. The corneas are clear. No erythema of the lids is appreciated. Anterior chambers are clear and extraocular movements are conjugate but not fully testable, though the Doll's eye maneuver was normal. There is no preauricular lymphadenopathy.
At this point,
what is your working differential diagnosis?
- non-accidental trauma,
- accidental trauma,
- hyperthyroidism,
- periorbital or orbital cellulitis,
- orbital malignancy (e.g., retinoblastoma),
- other.
How would you proceed?
- visual acuity testing,
- complete blood count,
- eye culture,
- ophthalmology consult,
- all of the above,
Answer:
- all of the above.
Culture of the eye discharge or conjunctiva is needed to rule out bacterial conjunctivitis. Blood work for thyroid function and complete blood count (CBC) is useful to check for other etiologies of the proptosis and for the possibility of hematologic malignancy. Visual acuity testing should be done in every case of symptoms related to the eye. Ophthalmology is needed because of the possibility that surgical intervention my be indicated.
His visual acuity is probably normal, but this is difficult to test well in a 2 year old. His CBC is normal and eye cultures were obtained. An ophthalmology consult was obtained and a CT of the orbits is ordered. View CT scan.
What does the CT show? Does this alter your differential? What should be done now?
The CT of this child's orbits reveals thickening of the orbital structures. Thickening/swelling of the extraocular muscles is most evident. No calcifications are noted. The globes are normal and no bony erosions are noted. The remainder of the study is normal. These findings are consistent with orbital pseudotumor.
The arrows here point to the enlarged extraocular muscles resulting in anterior displacement of the globe. Although the arrows point fo just some of the lateral and medial rectus muscles, ALL the extraocular muscles are enlarged.
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Discussion
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Orbital pseudotumor (OP) or idiopathic non-specific orbital inflammation is a non-infectious acute inflammation of the orbits, that presents with orbital swelling or a mass. It is usually unilateral, but it may be bilateral as it was in this case. It is uncommon in children but it has been reported in children as young as 3 months of age. OP may present as proptosis, eye pain, ptosis, lid edema, conjunctivitis with or without chemosis (swelling of the conjunctiva) and limitation of extraocular movements. Fever, headaches and eye discharge may be found. Orbital involvement is generally unilateral and recurrences may occur. Sometimes one can palpate a mass above the temple or under the orbital rim. Autoimmune disorders have been associated with this condition. The differential diagnosis includes orbital cellulitis, orbital abscess, tuberculoma, hematoma, inflammation secondary to systemic disease such as Grave's disease, sarcoidosis, a retained foreign body, leukemia, lymphoma, optic neuritis, tumors (primary, metastatic and pseudo).
To establish a diagnosis, ultrasonography and/or CT of the orbits is often necessary. Special laboratory studies such as markers for rheumatoid disease or thyroid dysfunction may also be helpful. The CT typically demonstrates diffuse anterior orbital inflammation next to the globe with scleral and choroidal thickening. Enlargement of the extraocular muscles may also be seen on either ultrasound or CT scan.
After an imaging diagnosis is made, a biopsy may be necessary to rule out leukemia or lymphoma. The histopathology of orbital pseudotumor shows polymorphic lymphocytic and plasmacytic infiltrates with eosinophilia. Corticosteroids are the mainstay of therapy. Once started, the symptoms quickly resolve as they did in our case. In fact, the response to steroids is so pathognomonic, that the diagnosis is often made retrospectively based on the response. A poor response indicates the need for biopsy.
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References
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- Grossniklaus HE, Lass JH, Abramowsky CR, Levine MR. Childhood orbital pseudotumor. Ann Opthalmol 1985;17(6):372-377. Sirbaugh PE. A case of orbital pseudotumor masquerading as orbital cellulitis in a patient with proptosis and fever. Ped Emerg Care 1997;13(5):337-339.
Copyrighted:- Radiology Cases in Pediatric Emergency Medicine Volume 6, Case 10
Loren Yamamoto, MD, MPH, Professor of Pediatrics, University of Hawaii John A. Burns School of Medicine. Loreny@hawaii.edu
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