Pachymeningitis in a Patient With Granulomatosis With Polyangiitis; A Case Report

Introduction: Granulomatosis with polyangiitis (GPA) is a systematic and necrotizing vasculitis with positive autoimmune antibodies. Some studies have 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 central nervous system (CNS) involvement, while there were no definite features of sinusitis or kidney injuries. Case Presentation: A 15-year-old girl was admitted because of blurred vision in her left eye. She was a known case of GPA three 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 the right eye was good, while the visual acuity in the left eye decreased to the point of finger counting at a distance of 20 cm. The left eye Marcus gunn test was positive (3+); anterior and posterior eye segments were normal. The patient was evaluated by brain MRI with gadolinium and a pathologic enhancement in the left cavernous was seen which had a pressure effect on the 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 a biopsy to confirm a diagnosis. In our case, the imaging manifestation was heterodox for granuloma, while neurosurgical consultation recommended drug treatment for pachymeningitis.