Late complications of radiosurgery for cerebral arteriovenous malformations: report of 5 cases of chronic encapsulated intracerebral hematomas and review of the literature

Abstract

Background: Chronic encapsulated intracerebral hematomas (CEIHs) are a rare, late complication of radiosurgery for intracranial AVM. We present 5 cases treated mostly by surgical excision and review the literature. Methods: Patients (age 39, 42, 36, 31, 62) presented with headache, paresthesia, hemiparesis or were asymptomatic. CEIHs presented 10 to 13 years (median 12 years) post radiosurgery. Three patients had demonstrated early radiation induced changes post radiosurgery. Angiographic cure, assessed with DSA, was present in all cases except 1 case with a small nidus remnant. MRI demonstrated mixed lesions with a solid enhancing part, organized hematoma and extensive surrounding edema while three cases had also a cystic component. Results: Excision of the CEIHs with complete or partial removal of the capsule was performed in 4 patients and resulted in marked clinical improvement. One patient was managed conservatively with administration of steroids as surgery was judged excessively hazardous with eventual stabilization of his symptoms. Conclusions: CEIHs are rare, late complications of radiosurgery for cranial AVM. They may be asymptomatic or provoke symptoms and may be preceded by early radiation induced changes. Complete removal of CEIHS is an effective treatment. Because of the long latency period of CEIHs, patients who had radiosurgery for brain AVMs should be followed by MRI at least 10 years even after complete obliteration.

Chronic Encapsulated Intracerebral Hematoma as an Occasional Finding in Sudden Cardiac Death

“…CEIH is a rare entity, and the exact origin is still very challenging for the pathologist [ 1 , 3 ]. It is a disease affecting all ages; the youngest reported patient was 2 months old and the oldest was 80 years old.…”

“…Several factors can cause a CEIH. It can be related to an old trauma or a vascular malformation, cavernoma, micro-aneurysm, and venous angioma and it is also described as a complication of SRS for AVM [ 3 , 4 , 14 , 15 , 16 ]. Thrombosis or vascular damage followed by a small intracranial hemorrhage could lead to the formation of a chronic organized hematoma [ 17 ] but the mechanism of the capsule formation, the progressive expansions and eventually its resolution is still unclear [ 6 ].…”

“…Organized hematomas could be the result of a gamma knife radiosurgery (GKR) for cerebral-AVM even though the development of chronic organized hematomas remains unclear [ 16 ]. Finitsis et al (2020) reported an incidence of 1.8% of patients with brain-AVM treated with SRS over a period of 17 years, highlighting that the latency time from radiosurgery to CEIHs diagnosis was 7.7 years (sd 3.7 years) [ 3 ]. It has also been suggested that the possible initial cause of CEIH can be minor recurrent bleeding from fragile vessels within radionecrotic brain tissue.…”

“…Differently from an intracerebral hemorrhage which shows a sudden onset, CEIH often begins with progressive neurological deficits due to the mass effect [ 1 ]. Sometimes, it is associated with vascular lesions such as arteriovenous malformation (AVM), cavernous malformations, capillary telangiectasia, micro-aneurysm, mixed or unclassified angiomas and stereotactic radiosurgery (SRS) for AVM [ 2 , 3 , 4 , 5 ]. The size of a CEIH is related to the amount of the hemorrhage, to the obstruction to the blood outflow and the amount of adjacent damaged tissue.…”

Frameless versus frame-based stereotactic radiosurgery for intracranial arteriovenous malformations: A propensity-matched analysis

“…Radionecrosis was defined as a lesion with a central rim or irregular nodular enhancement with or without edema and it was reported by a neuroradiologist [29] . Cyst formation and chronic encapsulated hematoma were subtypes of late AREs [27] , [30] , [31] . Hemorrhage in the latency period was defined as any bleeding of AVM after the SRS before complete obliteration was achieved, and its incidence was calculated by 100 person-years at risk.…”