Teaching NeuroImage: Intracerebral Seroma Secondary to Arterial-Venous Malformation

A 44-year-old man presented with worsening weakness of the right upper and lower limbs and a 26-year history of epilepsy. Images showed a cyst-like mass with hemosiderin deposition in the left hemisphere neighboring an arterial-venous malformation (AVM) (Figure). Imaging findings were consistent with seroma secondary to an AVM.1 After receiving oral antiepileptic treatment, muscle strength of affected limbs recovered from grade 4 to 5. Seroma usually occurs as a complication of radiosurgery2; few cases are attributed to untreated intracerebral AVMs. This case suggests that intracerebral seroma associated with AVMs could be a long-term consequence of prior intracranial bleeding episodes.