Neurology

A 55-year-old woman had right exophthalmia. Eleven years previously, she had orbital irradiation for refractory nonspecific orbital inflammation. PET/CT revealed FDG uptake in the right orbit and paravertebral masses (figure 1, A and C). MRI showed an enlargement of the right optic nerve and orbital muscles, and a diffuse infiltration involving lumbodorsal and sacral nerve roots (figure 1, B and D). The orbital biopsy demonstrated immunoglobulin G4 (IgG4)+ plasma cell infiltrate and a storiform fibrosis (figure 2), identical to the histopathologic features of the nerve root biopsy, and suggestive of IgG4-related diffuse perineural disease.1,2 No treatment was started in the absence of neurologic symptoms. One year later, the patient had no further symptoms.