IgG4-related perineural disease

Aims. To elucidate characteristics of IgG4-related disease involving the peripheral nervous system. Methods. Retrospective review of 106 patients with IgG4-related disease identified 21 peripheral nerve lesions in 7 patients. Clinicopathological and radiological features were examined. Results. Peripheral nerve lesions were commonly identified in orbital or paravertebral area, involving orbital (n=9), optic (n=4), spinal (n=7), and great auricular nerves (n=1). The predominant radiological feature was a distinct perineural soft tissue mass, ranging 8 to 30mm in diameter. Histologically, the epineurium was preferentially involved by massive lymphoplasmacytic infiltration rich in IgG4 plasma cells. All lesions were neurologically asymptomatic and steroid-responsive at the first presentation, but one recurrent lesion around the optic nerve caused failing vision. Conclusion. IgG4-related disease of the peripheral nervous system is characterized by orbital or paravertebral localization, perineural mass formation, and rare neurologic symptoms. The term IgG4-related perineural disease seems appropriate to describe this entity.