This editorial in Survey of Ophthalmology argues for abandoning corticosteroid trials for undiagnosed orbital inflammation in favor of a rigorous clinical, radiological and pathological workup.
Since 1985, the diagnostic standard for orbital inflammation has been administration of a short, high-dose course of corticosteroid to reveal whether the patient is suffering from idiopathic orbital inflammation (IOI) or a separate condition. The issue at hand is that many diseases present with orbital inflammation, and many will respond, at least initially, to corticosteroids.
Of particular concern is the test’s inability to differentiate lymphoma and lymphoid hyperplasia from benign conditions, as they induce apoptosis in lymphocytic lesions causing a temporary clinical improvement in malignant disease. False diagnosis of IOI using this method has also been reported for cases of metastatic disease, epithelial lesions of the lacrimal gland, fungal infections, granulomatosis with polyangiitis (GPA), and sarcoidosis.
Furthermore, some cases of biopsy-confirmed IOI subtypes do not even respond to corticosteroids. Recent studies found that 21% of patients with idiopathic dacryoadenitis and 45% of patients with sclerosing IOI are unresponsive to the high corticosteroid doses.
However, the authors assert that therapeutic administration of corticosteroids is still of great benefit in many situations. Prompt corticosteroids may save vision in IOI lesions associated with optic neuropathy and provide relief for severe idiopathic orbital myositis. Yet in such cases it is important to remember that a clinical response is not diagnostic, and the next steps should involve a thorough examination for other diseases.
After clinical examination, radiological investigation should be considered. Unfortunately, imaging will typically only narrow the suspect pool rather than provide diagnosis.
The authors believe that pathological analysis is critical for elucidating the etiological agent in the context of the previous findings. Histological analysis can quickly rule out many conditions, for example, IOI, Immunoglobulin G4-related disease (IgG4-RD) and GPA are distinctive to malignancies and lymphoproliferative disorders even with macroscopic examination. In addition, features such as granulomas or vasculitis and tissue necrosis may point to sarcoidosis or GPA, respectively.
Orbital tissue samples can now be obtained with minimally invasive procedures, though open surgical biopsy is still preferable to needle aspiration as it retrieves more tissue. Whichever method is used, the physician should take samples from multiple parts of the lesion.
Though exceptions remain for lesions on the orbital apex or on optic nerve (as obtaining a biopsy in those locations has high risk of morbidity), the authors maintain that corticosteroid trials for undiagnosed orbital inflammation are too weak to identify a diagnosis in orbital inflammation.