Cyclophosphamide responsive primary angiitis of the CNS in a 61-year-old female

Dear Sir – A 61-year-old female with no significant past medical history presented with flu like symptoms including fever, chills and headaches after returning from a trip to Hawaii. First saw her primary care physician who advised conservative management. A couple of days later, she presented with worsening of her headaches and was admitted for meningitis work up. The neurologic exam was unremarkable. A lumbar puncture revealed a pleocytosis with 206 WBC and an elevated total protein of 75 mg/dl. PCR was negative for West Nile, HSV and enterovirus. Malaria smear, leptospira, and cryptococcal antigen were also negative. A brain MRI was unremarkable except some slight periventricular T2 changes near the anterior horn of the lateral ventricle. She was eventually discharged with presumptive diagnosis of aseptic meningitis. However, she failed to improve with persistent nausea and unsteadiness of gait and vision gradually became blurry. A repeat brain MRI showed multifocal abnormal T2 prolongation in periventricular regions (Figure 1A, B) with contrast enhancement on T1-weighted images (Figure 1C). In addition, MRI of cervical, thoracic and lumbar spine showed significant T2 signal changes in the cervical and thoracic cord with enhancement, both patchy and confluent. She underwent a brain biopsy and the preliminary pathology was concerning for lymphoma or vasculitis. Intravenous methylprednisolone was initiated afterwards and the patient improved immediately. The pathology revealed white matter with perivascular cellular infiltrates. Lumens were nearly obliterated by reactive endothelial cells and, percolating through the blood vessel walls, were populations of predominantly small mature appearing lymphocytes (Figure 2A) accompanied by reactive microglia or macrophages. The inflammatory infiltrates showed no significant cytologic atypia. The blood vessel walls, while perturbed by the passing lymphocytes and microglia, did not show fibrinoid necrosis. No granulomas were identified. Surrounding parenchyma was hypercellular as a result of infiltration