Objective:

To report a case of and review the literature for mechanical thrombectomy-associated foreign body granuloma and discuss the benefit of early recognition and intervention.  

Background:

Mechanical Thrombectomy (MT) carries the risk of releasing hydrophilic polymer substances that can cause foreign body granulomas. Our case highlights a 69-year-old woman with MRI findings after thrombectomy revealing punctate T2 FLAIR hyperintensities in the right parietal lobe with associated enhancement and vasogenic edema. Due to this, she presented multiple times with episodes of transient confusion, disorientation, headache, and nausea. To date, there are only a few cases of foreign body granulomas after MT in the literature. This condition is not fully understood; however, it is a risk associated with using endovascular devices. Early recognition and diagnosis of MT associated granuloma formation is important to reduce patient morbidity. 

Design/Methods:

Retrospective evaluation of patient chart, including demographic information, history, clinical presentation, examination, imaging and laboratory work-up, and therapies were evaluated.

Results:

The case demonstrates mechanical thrombectomy (MT) complicated by recurrent granulomatous inflammation.  The management consisted of high dose dexamethasone and a taper, followed by serial imaging for continued monitoring, demonstrating reduction in edema and nodule size, and improvement of her symptoms. However, the inflammation recurred each time steroids were tapered. Lesions were presumed to be granulomatous foreign bodies, based on appearance. Biopsy results of the right parietal dura and lesion demonstrated mild leptomeningeal mononuclear cell inflammation; however, this was influenced by steroid use.

Conclusions:

The possibility of foreign body granulomas should be considered in patients with worsening clinical symptoms after mechanical thrombectomy, or with imaging findings of nodular-appearing FLAIR hyperintensities and cerebral edema after thrombectomy. Recurrent granulomatous changes after thrombectomy is a rare clinical entity and should be swiftly recognized. With increased awareness, we can identify this adverse effect sooner, reduce costs and improve patient outcomes.