Introduction: Granulomatosis with polyangiitis is a systematic and necrotizing vasculitis with positive autoimmune antibodies. Some studies have been reported the prevalence of eye involvement between 40-50% of cases. Retro orbital granuloma is a rare complication of GPA which should be treated by surgical involvements, while pachymeningitis can be diagnosed by MRI and treated by medical management. .in this study, we tried to present a case of GPA with optic neuritis and typical CNS involvement, while there was no definite features of sinusitis or kidney injuries.
Case presentation: A 15 years old girl was admitted because of blurred vision in left eye .She was a known case of granulomatosis with polyangitis from 3 years ago with initial features including left facial nerve paresis due to pan-sinusitis and pulmonary cavity. Neurologic evaluations including sensory and motor features were normal, too. Ophthalmologic examinations showed that visual acuity of right eye was good, while it was decreased till finger count in near distance (20 centimeters) in left eye. Left eye Marcusgann test was positive (3+), anterior and posterior eye segment were normal. The patient evaluated by brain MRI with gadolinium and a pathologic enhancement in left cavernous was seen which had pressure effect on optic nerve. She was treated by intravenous methylprednisolone followed by rituximab.
Conclusion: Reporting orbital mass in a patient who had GPA can be supposed as granuloma which needs biopsy to confirm diagnosis. In our case, the imaging manifestation was heterodox for granuloma, while neurosurgery consult recommended us to treat the patient for pachymeningitis.