Inflammatory orbital pseudotumor can affect any or all structures within the orbit. The inflammatory response can be nonspecific, granulomatous, or vasculitic or due to reactive lymphoid hyperplasia. The inflammation can be part of an underlying medical disorder (eg, IgG4-related orbital disease or granulomatosis with polyangiitis) or can exist in isolation. Patients of all ages can be affected. The process can be acute or chronic and can recur.
Symptoms and signs of inflammatory orbital pseudotumor typically include a sudden onset of pain along with swelling and erythema of the eyelids. Proptosis, diplopia, and vision loss are also possible. In cases of reactive lymphoid hyperplasia or IgG4-related orbital disease, there are typically few symptoms other than proptosis or swelling.
Similar findings occur with inflammatory orbital pseudotumor and orbital infection, but there is no history of trauma or adjacent focus of infection (eg, sinusitis) with inflammatory orbital pseudotumor. Neuroimaging with CT or MRI is required. A useful imaging feature in distinguishing an infection from noninfectious inflammation is the presence of adjacent sinus involvement in orbital infection. For chronic or recurrent disease, biopsy may be used to find evidence of an underlying medical condition.
Treatment for inflammatory orbital pseudotumor depends on the type of inflammatory response and may include oral corticosteroids, radiation therapy, and one of several immunomodulating drugs. In difficult cases of inflammatory orbital pseudotumor, particularly those with granulomatous inflammation, some initial success has occurred with monoclonal antibodies against tumor necrosis factor (TNF)-alpha or with lymphocyte depletion using rituximab, if the inflammation is primarily vasculitis.