The spectrum of orbital inflammatory disease (OID) ranges broadly from specific disease diagnoses, for example, Wegener’s granulomatosis or sarcoidosis, to nonspecific inflammation which may involve one or multiple structures of the orbit. Mimics of idiopathic OID must be considered in a comprehensive differential diagnosis and include malignancies, congenital mass lesions, infectious diseases, and occult or distant trauma. Idiopathic OID may be secondary to an underlying systemic inflammatory disease, which must be diagnosed in order to develop a comprehensive therapeutic plan, or may represent localized pathologic processes without systemic involvement. Evaluation of the patient with suspected OID must include a careful history, physical examination, directed laboratory, and radiologic studies, and may sometimes require tissue for diagnostic studies. Therapeutic options for inflammatory diseases are expanding as biologically targeted agents become available that act on specific segments of the inflammatory cascades. The purpose of this paper is to provide a framework for the evaluation and management of patients with the spectrum of diseases known as OID and to discuss some of the new advances in immunologic monitoring and targeted immune therapies that will likely play an increasingly important role in the care of these patients.
Orbital inflammatory disease (OID) accounts for up to 6% of orbital diseases, affects all age groups of patients, and is a frequent cause for orbital biopsy. Differential diagnosis of OID ranges from idiopathic inflammatory disease to systemic or local inflammatory conditions to other associated conditions such as neoplasm, infection, congenital malformation, or trauma.14 Systemic inflammatory diseases associations of OID include autoimmune thyroid disease, sarcoidosis, Wegener’s granulomatosis, Crohn’s disease, systemic lupus erythematosis, and other connective tissue diseases, Churg–Strauss syndrome, Erdheim–Chester, histiocytosis X, and giant cell arteritis. Congenital lesions, in particular dermoid cysts but also lymphangiomas, may develop an inflammatory component or alternatively may create intermittent signs and symptoms that may mimic OID.49 Primary tumours of the eye, for example, malignant melanoma, may develop extra-scleral extension eliciting a secondary orbital inflammatory process. Both primary and metastatic tumours in the orbit may have inflammatory components and rhabdomyosarcoma in particular may mimic inflammatory disease. Infectious diseases secondary to bacteria, viruses, fungi, and parasites may produce significant inflammatory disease and must always be considered as a potential diagnosis in any patient with OID. The key to developing a rational differential diagnosis and therapeutic plan is a comprehensive approach to patients with symptoms or signs of orbital inflammation.