The following case elucidates a rare complication of a foreign body reaction to the hydrophilic coating fragments of the pipeline embolization device.

Intracranial aneurysms (IAs) are pathological dilatations of intracranial arteries. Unruptured IAs have a prevalence of 3% in the adult population worldwide. Endovascular treatment (EVT) is a common first line preventive repair for unruptured intracranial aneurysm.

50-year-old female presented to the ED with acute onset left-sided weakness of the upper and lower extremities and left-sided facial numbness 20 days following treatment of an unruptured anterior communicating artery aneurysm with Pipeline Flex Embolization Device (PED). Patient’s significant medical history includes multiple sclerosis (MS), rheumatoid arthritis, Crohn’s disease managed with Humira, and diabetes. The CT head without contrast showed confluent edema within the right MCA watershed region, suspicious for infarct. However, the CTA of head showed no vessel occlusion with a patent PED. Brain MRI identified numerous enhancing lesions throughout the right cerebral hemisphere with internal cavitations and significant perilesional vasogenic edema with regional mass effect without midline shift. Empiric antibiotics and antifungal were initiated to cover both typical and atypical causes due to Humira use for Crohn’s disease. Labs, blood cultures and CSF results were insignificant. Pulse-dose steroid for 5 days was started, after 72-hr negative blood cultures. Over time, the patient’s symptoms improved, and she regained her strength back. A repeat brain MRI after the course of steroids showed diminished enhancement, size, and number of brain lesions. The patient was discharged home on a long Prednisone taper and long-term intravenous vancomycin, ceftriaxone, and oral metronidazole.

Foreign body reactions are rare complications of EVT. It is important to be aware of possible foreign body emboli in patients with the enhancing brain lesions located in the same vascular territory where the recent endovascular procedure was performed.