Intracranial Granulomatous Reaction

These images show multiple dural-based rim and solidly enhancing masses along the olfactory groove and frontal cranial fossa with peripheral hemosiderin and areas of central restricted diffusion which could be concerning for abscess formation or recurrence depending on the timeline. There is surrounding T2 FLAIR hyperintensity compatible with vasogenic edema. This patient had previously undergone resection of a planum sphenoidale meningioma and subsequently developed these enhancing collections and masses. These were subsequently debrided and pathology showed them to represent foreign body granulomas which developed in reaction to cotton fibers which is commonly used for hemostasis in neurosurgery.