Retrospective Analysis on 76 Cases of Cerebral Arteriovenous Malformations Treated by Gamma Knife Radiosurgery

OBJECTIVE: Outcome of gamma knife radiosurgery (GKS) in the consecutive 100 cases with cerebral arteriovenous malformations (AVMs) was analyzed. METHODS: Data from initial 100 patients treated with GKS in the authors' institute were reviewed retrospectively. Spetzler-Martin grade at diagnosis were I in 18 patients, II in 27, III in 36, IV in 11, and V in 8. Thirty-five patients had experienced previous bleeding, 27 patients presented with seizure, and 31 patients presented with headache. The mean volume of the lesion was 4.3 cm3 (0.1-29.3 cm3). The median radiation dose delivered to the margin was 20.0 Gy (13-32 Gy). Mean follow-up period was 37.5 months (5-63 months). RESULTS: Angiographic follow-up was performed in 48 patients at least 2 years after GKS. Sixteen patients were lost in follow up following 2 years from GKS. Twenty-eight of 48 patients (58%) showed complete obliteration and 20 patients (42%) showed partial obliteration. Seven patients presented with post-GKS hemorrhage. Adverse radiation effect (ARE) was observed at follow-up MRI in 25 of 76 patients, and it was symptomatic in 5 patients. Complete obliteration was confirmed in 24 of 31 (77%) patients with volume less than 4 cm3, meanwhile only 4 of 17 (24%) patients with volume of 4 cm3 or more showed complete obliteration. Complete obliteration rate was 67% with 20 Gy or higher marginal dose, 63% with 15-20 Gy, and 17% with less than 15 Gy. CONCLUSION: GKS can provide high rates of obliteration with acceptable risk of morbidity in a subgroup of small AVMs. However, overall outcome in whole spectrum of AVMs, in which large proportion of cases have unfavorable characteristics for radiosurgery, is much worse. More effective therapeutic strategy needs to be developed for large AVMs that are difficult to be managed with current available treatment modalities.

Aneurysmal Bone Cyst Arising from Iliac Bone Mimicking Liposarcoma

Aneurysmal bone cysts (ABCs) are benign, non-neoplastic, expansile lesions. We present a case of a male patient aged 46 presented with 4-month history of left hip and low back pain and left hip swelling. Lumbosacral magnetic resonance imaging (MRI) and computed tomography (CT) demonstrated a large multi-loculated hemorrhagic lumbosacral and retroperitoneal mass with spinal dysraphism and tethered cord. Curettage and Biopsy were performed with partially resected cystic wall which was histological confirmed with aneurismal bone cyst. Large cystic mass of the vertebrae, sacrum, and pelvic bone must be considered with ABCs.