Symptomatic Granuloma Secondary to Embolic Agent: A Case Report

Abstract

A 24-year-old female presented with weakness of left upper limb and an episode of generalised seizure. She had a history of right parieto-occipital Arteriovenous Malformation (AVM) which was embolised in four settings with different embolic agents (glue, polyvinyl alcohol). She had received Gamma Knife Surgery (GKS) for residual AVM. Post radiosurgical procedure, there was complete obliteration of AVM which was confirmed on angiography. However, she had developed an intracranial Space Occupying Lesion (SOL) at the site of AVM with atypical imaging features [Table/ Fig-1]. Surgical excision of this lesion was carried out and histological examination of the specimen showed a foreign body reaction.She then came to our institute with weakness of left upper limb and an episode of generalised seizure. Gadolinium contrast MRI showed multiple conglomerate ring enhancing lesion at right parieto-occipital region with mass effect [Table/ Fig-2]. Computed Tomography (CT) scan showed artefacts due to the presence of onyx . We proceeded to do a re-exploration of the previous craniotomy and microsurgical excision of the contrast enhancing lesion. It was a firm mass which was excised completely in piecemeal fashion. Histopathological examination showed an AVM nidus with necrotising granulomatous inflammation with predominant foreign body giant cell reaction. The patient made a good postoperative recovery and has had an uneventful follow-up for the last one year. ABSTRACTOnyx is a liquid embolic agent presently gaining wide acceptance for embolisation of multiple vascular cranial pathologies like Arteriovenous Malformation (AVM) and Arteriovenous Fistula (AVF). Onyx stays in the nidus of vascular pathology and initiates inflammatory response leading to thrombosis and subsequently resulting in occlusion of vascular nidus. However, if onyx spills into the surrounding brain tissue, reaction occurs in the form of foreign body inflammatory reaction. This is one of the very few cases in literature whereby embolisation of AVM with onyx lead to granuloma formation which needed surgical excision. It presented with limb weakness and seizure episodes.[

Foreign body granuloma reaction after endovascular therapy of an unruptured right frontal arteriovenous malformation

“…In this patient, Onyx and two more different embolic substances were used, thus making more difficult a precise definition of the etiopathogenesis. 6) A foreign body granuloma reaction to Onyx embolization for a congenital orbito-facial vascular malformation was also reported. The histopathological findings of this extracranial AVM included Onyx particles partially impacted in small vessels and numerous multinucleated giant cells that had phagocytosed the Onyx particles.…”

“…4)6)8) Only one case report on a cerebral foreign body granuloma reaction to Onyx was found in the literature. 6) Murayama et al conducted a histopathological study in swine rete mirabile before Onyx introduction into the market. They demonstrated that Onyx generates a perivascular inflammatory reaction in subacute (18 days) and chronic (one to six months) stages with a granulomatous response characterized by the presence of epithelioid and multinucleated foreign body giant cells.…”

“…They concluded that the occurrence of chronic foreign-body giant cells and recanalization after Onyx embolization shows a long-standing reaction to Onyx. 10) Gunawat et al 6) reported about the occurrence of a parieto-occipital foreign body granulomatous reaction in a patient who had undergone embolization and four radiosurgery sessions for an AVM. Multinucleated foreign body giant cells were predominant at the histopathological examination.…”

“…On the other hand, various Onyx embolization-related complications have been reported [ 7 , 11 - 13 ]. Foreign body granulomas to the embolizing agents are very rare [ 4 , 6 , 8 ]. Only one case report on a cerebral foreign body granuloma reaction to Onyx was found in the literature [ 6 ].…”

“…Only one case report on a suspected cerebral foreign body granuloma reaction to Onyx was found in the literature. 6) Here, we report the occurrence of a cerebral foreign body granuloma in a patient who underwent embolization of an unruptured right frontal AVM. The histopathological findings were highly compatible with a cerebral foreign body granuloma reaction to Onyx.…”