Infraorbital nerve enlargement linked to reactive lymphoid hyperplasia

This case series suggests that enlargement of the infraorbital nerve and canal is indicative of reactive lymphoid hyperplasia or IgG4-related disease, especially in the presence of ipsilateral extraocular muscle enlargement, sinus disease or orbital disease.

The authors present 14 patients with proptosis and periocular pain, all experiencing some extraocular muscle enlargement.About half of the cases were categorized as IgG4-related disease on histologic review. All patients had sinus disease and enlarged extraocular muscles, and two thirds also had lacrimal gland enlargement. 

Although infraorbital nerve enlargement has been recently described as being almost pathognomonic or suggestive of IgG4 disease in some patient groups, this series suggests that this process can occur with other diseases, namely, reactive lymphoid hyperplasia. 

All patients responded well to systemic corticosteroid therapy, although some relapsed upon withdrawal. One patient developed diffuse large B-cell lymphoma and subsequently leukemia.

Future studies may determine whether geographic variations or ethnicity contribute to differences in the cause of infraorbital nerve enlargement or other trigeminal nerve enlargement in reactive lymphoid hyperplasia and IgG4-related disease.