IgG4-related disease or Graves orbitopathy
Reviewed by James Hsuan

This is retrospective review of patients who had been diagnosed with both IgG4-related ophthalmic disease (IgG4-ROD) and Graves orbitopathy over a four year period. Eight patients were identified. The diagnosis of IgG4-ROD was based on 10 or more IgG4+ plasma cells per high power field on orbital biopsies. There were three sub-groups: two with Graves disease but atypical orbital disease who were later diagnosed with IgG4-ROD, four with IgG4-ROD only but were initially misdiagnosed as Graves orbitopathy, and two who had both diseases. The authors state there was no single clinical feature which could absolutely distinguish one disease from the other. However, IgG4-ROD was more likely in the presence of a disproportionately enlarged lateral rectus, enlarged infraorbital nerves, a history of asthma, orbital masses not involving the lacrimal gland, and proptosis with minimal inflammation. The diagnosis can be confirmed by a biopsy showing increased tissue IgG4+ plasma cells, or an IgG4+:IgG+ ratio of >40%, and a serum IgG4 concentration >135mg/dl. Graves orbitopathy was more likely with raised thyrotropin receptor antibodies and lid retraction or lag. The article only reports a small number of patients, but usefully highlights the overlap between the two conditions.

Distinguishing IgG4-related ophthalmic disease from Graves orbitopathy.
Tooley AA, Salomao DR, Bradley EA, Garrity JA.
OPHTHALMIC PLASTIC AND RECONSTRUCTIVE SURGERY
2019;35:170-6.