Histopathology of graves’ orbital disease
The histopathology of Graves’ orbital disease has been studied extensively over many decades. The bulk of evidence indicates that the extraocular muscles are the primary site of immunological attack and the resulting myositis causes the exophthalmos noted on clinical examination (1,2). However, many clinical, radiological, and histological studies have noted pathological changes in the orbital connective tissue, leading Nunery to categorize Graves’ ophthalmopathy into two subtypes that may occur separately or together (3). Nunery classified type 1 ophthalmopathy as showing “retrobulbar fat and connective tissue stimulation with increased fibroblastic activity, glycosaminoglycan deposition, and edema.'' Type 2 ophthalmopathy is characterized by extraocular myositis involving edema, lymphocytic infiltration, and muscle degeneration. Support for a distinct group of type 1 Graves’ ophthalmopathy is derived from radiological studies (4,5), but there has been no report of histopathologically confirmed abnormalities limited to retrobulbar fat and connective tissue, to my knowledge.
