Muslinoma and muslin-induced foreign body inflammatory reactions after surgical clipping and wrapping for intracranial aneurysms: imaging findings and clinical features

Abstract

Object Reinforcement of aneurysms with additional wrapping is an alternative procedure if the aneurysm cannot be completely clipped. Wrapping with muslin (cotton gauze) rarely incites foreign body inflammatory reactions. In this study, the authors describe the clinical and radiological features of muslinomas or muslin-induced foreign body reactions that can develop after treatment of intracranial aneurysms. Methods Over a 3-year period, 5 patients with muslinomas underwent treatment at the authors' institution. All patients underwent aneursym clipping and wrapping, and were subsequently readmitted with acute or subacute neurological symptoms. Clinical and imaging features on diffusion weighted MR images and cerebral angiography images were retrospectively reviewed. The patients' clinical course and follow-up imaging studies were also evaluated. Results In all 5 cases, muslinomas were seen as rim-enhancing inflammatory masses around the clipped aneurysms with perilesional edema visible on MR images at the time of clinical deterioration. The MR images also demonstrated adhesive arachnoiditis with a sterile intracranial abscess in 3 patients, optic neuropathy in 2, parent artery narrowing in 2, and a resultant acute ischemic infarction in 1 patient. Follow-up imaging revealed resolution of both the perilesional edema and adhesive arachnoiditis but no significant changes in the muslinomas. All patients underwent conservative management and fully recovered, but during the follow-up period, 2 patients experienced clinical and radiological relapses. Conclusions When a patient with a history of wrapping of an aneurysm presents with acute neurological symptoms and an enhancing intracranial mass in the region of the surgical site on MR imaging, a muslin-induced foreign body inflammatory reaction should be considered in the differential diagnosis, and careful clinical and radiological follow-up is advised.