Neurology India Medknow Publications on behalf of the Neurological Society of India ISSN: 0028-3886 EISSN: 1998-4022 Vol. 59, Num. 4, 2011, pp. 624-626

Neurology India, Vol. 59, No. 4, July-August, 2011, pp. 624-626

Case Report

Chronic encapsulated intracerebral hematoma formation after radiosurgery for cerebral arteriovenous malformation

Satoru Takeuchi¹, Yoshio Takasato², Hiroyuki Masaoka²

¹ Department of Neurosurgery, National Defense Medical College, Saitama, Japan
² National Hospital Organization Disaster Medical Center, Tokyo, Japan
Correspondence Address: Satoru Takeuchi, Department of Neurosurgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan, s.takeuchi@room.ocn.ne.jp

Date of Submission: 28-Dec-2010
Date of Decision: 31-Dec-2010
Date of Acceptance: 19-Jan-2011

Code Number: ni11185

PMID: 21891948

DOI: 10.4103/0028-3886.84352

Abstract

Keywords: Arteriovenous malformation, chronic encapsulated hematoma, intracerebral, radiosurgery

Introduction

Stereotactic radiosurgery (SRS) is accepted as an effective treatment modality for patients with a cerebral arteriovenous malformation (AVM). However, several delayed complications following SRS for AVM, including parenchymal hemorrhage, radiation necrosis, dural arteriovenous fistula, and cyst formation, have been reported in 3.2-19.8% of patients. ^[1] Chronic-encapsulated intracerebral hematoma (CEIH) is a rare cerebrovascular disease that behaves as a slowly expanding lesion with a gradual onset. ^[2] The structure of the capsule in CEIH consists of an outer layer of collagen and an inner layer of granulation tissue. It is well established that CEIH is associated with vascular malformations such as cavernous angioma, venous angioma, or AVM. ^[2] However, there are few reports of CEIH presenting after radiosurgery for AVM. ^{[3],[4],[5],[6]} Herein, we report a rare case of CEIH after SRS for AVM.

Case Report

A 49-year-old male presented with a right-sided facial numbness. Computed tomography (CT) showed hemorrhage in the left temporal lobe. Cerebral angiography revealed an AVM supplied by the anterior temporal branch of the middle cerebral artery (MCA) [Figure - 1]a and b. Transarterial embolization and surgical excision were performed. Follow-up cerebral angiography 8 months after surgery showed no residual nidus. However, another AVM supplied by the cortical brunch of the MCA was detected [Figure - 1]c and d. Twelve months after surgery the patient underwent SRS (linear accelerator radiosurgery [LINAC], with a marginal dose of 18 Gy) for the AVM supplied by the cortical branch of the MCA. Follow-up CT 3 days later showed no abnormal findings and 14 months after SRS the patient presented with aphagia. Magnetic resonance imaging (MRI) showed a small-enhancing lesion close to the left lateral ventricle and marked white matter edema [Figure - 2]a. At that time a diagnosis of radiation-induced necrosis was made. Steroids were administered resulting in transient neurological improvement, whereas the white matter edema observed by MRI fluctuated in extent. 34 months after SRS, the patient presented with numbness of the right upper and lower extremities. CT showed a small hematoma in the left basal ganglia [Figure - 2]b. The patient was kept under observation. 43 months after SRS, the patient presented with memory disturbance. MRI showed a small-enhancing mass close to the left lateral ventricle, with a hematoma cavity in the basal ganglia [Figure - 2]c and d. Cerebral angiography revealed no visible residual nidus [Figure - 2]e. Surgical excision was performed. Description of operative findings Histological examination revealed that the capsule consisted of an outer collagenous layer and an inner granulated layer with deposits of hemosiderin, which was compatible with CEIH [Figure - 3]. There was no evidence of residual AVM (to be confirmed) postoperative course was uneventful.

Discussion

Although CEIH is a rare entity, it has been reported with increasing frequency in recent years. Approximately 60 cases with CEIH have been previously reported. ^[6] However, to the best of our knowledge only seven cases of CEIH after radiosurgery for AVM, including the present case, ^[4] have been reported. ^{[3],[4],[5],[6]} The clinicoradiological features of all seven cases are summarized in [Table - 1]. Interesting features of patients with CEIH after radiosurgery include a male predominance (male:female ratio 5:2), high frequency of basal ganglia involvement (6 of 7 patients), long interval from radiosurgery to diagnosable CEIH formation (mean, 5.4 years; range, 2-11 years), and high rates of presence of residual nidus (all patients received surgical excision). There were differences in types of SRS (Gamma knife (GK) in four patients, LINAC in three patients) and marginal doses (18-22.5 Gy). Nevertheless, further studies on the relationship between types of SRS or dose and the incidence of CEIH are required.

The incidence of occurrence of CEIH following SRS for AVM is largely unknown. Maruyama et al. reported a 0.6% incidence of CEIH after SRS for AVM (3 of 500 patients treated with GK), ^[4] markedly less than that of other complications such as delayed radionecrosis(2.2-9%). ^[7] However, the mechanisms of CEIH are unclear although similarities to chronic subdural hematoma (CSH) have been reported. ^[8],[9] The structure of the capsule has been shown to consist of an outer layer of collagen and an inner layer of granulation tissue in both CEIH and CSH. Further, high concentrations of vascular endothelial growth factor (VEGF) in the hematoma of both CEIH and CSH, indicating increased angiogenesis, have been reported. ^[8],[9] Nakamizo et al. also recently reported that activation of the VEGF pathway, may lead to CEIH formation after radiosurgery for AVM. ^[6]

We suggest that at least a 10 year careful follow-up is required for patients receiving radiosurgery for AVM, especially those in the basal ganglia with a residual nidus. The management of CEIH is controversial. As CEIH formation after radiosurgery for AVM indicates a high possibility of residual nidus, even if cerebral angiography cannot detect an abnormal lesion, surgical excision should be recommended if possible.

References

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