Orbital Pseudotumor: A Mimic of Orbital Cellulitis

Orbital pseudotumor (OP) also referred to as Non-specific orbital inflammatory syndrome (NOIS) has been associated with a wide range of inflammatory and autoimmune disorders and the exact etiology of this syndrome remains unknown. The differentiation of orbital cellulitis (OC) from OP is often complex leading to delays in appropriate treatment. Timely decision is crucial as both conditions are associated with intracranial complications and result in loss of vision. As compared to the few cases reported in literature, our case is unusual due to a history of mild chronic, relapsing-remitting course for over a year, without a clear diagnosis. Diagnosis is by exclusion, based on a thorough history, clinical presentation, and rapid response to corticosteroid treatment. It mimics orbital cellulitis or malignant lymphoma of the orbit because of the overlapping clinical manifestations. Our case emphasizes the importance of including this entity in the differential diagnosis of orbital cellulitis and the need for timely diagnosis and treatment to halt the progression of disease. This article provides a brief overview of OP, critical nature of the condition, clinical clues to diagnosis, and novel treatment options (steroid sparing agents) currently available for this condition. OP and NOIS are used interchangeably in this document.