New nidus found adjacent to the target site of AVM treated with Gamma Knife radiosurgery - Report of 3 casesDo Hoon Kwon1, Byung Duk Kwun2, Jae Seung Ahn2, Do Hee Lee2, Hyun Jung Kim21Seoul, Korea, Republic Of 2Asan Medical Center Keywords: arteriovenous malformation, outcome, gamma knife, radiosurgery, Imaging
A new AVM nidus was rarely found adjacent to the resecting margin of nidus after surgical resection of the AVM especially in the young age group.
But the new nidus adjacent to the target site of AVM treated with
radiosurgery had not been reported yet. We reported and reviewed our
case experiences retrospectively.
No patient had been treated with embolization before radiosurgery. All
patent had a history of ICH before or after reradiosurgery.
The authors retrospectively analyzed their experience in 1,000 cases of AVMs treated with Gamma Knife surgery during 20 years. Among them, 3 cases of new nidus were found adjacent to the target site with an incidence rate of 0.3%.
First patient was a 9 year old boy who treated with Gamma Knife for left occipital AVM one month after ICH. Treated volume was 600 cumm and 25Gy was irradiated to the margin of the nidus. Thirty one months after radiosurgery, the patient had have 2nd radiosurgery for the new nidus which was found adjacent to the target site, treated volume was 900 cumm. Second patient was a 9 year old boy treated with Gamma Knife for the small AVM located in the cerebellar vermis 1 month after bleeding. Five years after radiosurgery, he had rebleeding and retreated to the same nidus with Gamma Knife 2 month after rebleeding. Six years after 2nd treatment, he had a new nidus adjacent to the target site and the volume was increased from 400 cumm (2nd treated volume) to 2,800 cumm. He had have 3rd radiosurgery for this new nidus. Third patient was a 33 year old man who treated with radiosurgery for the incidentally detected cerebellar AVM, the nidus volume was 1,100 cumm and 20 Gy was irradiated to the nidus. Three years after radiosurgery, patient had cerebellar ICH and new nidus was found adjacent to the target site and 2nd radiosurgery was performed, the nidus volume was 500 cumm.
This was a small retrospective series.
A new nidus may develop adjacent to the target site after AVM radiosurgery, but the incidence appears to be very rare.
Physicians should be aware that a new nidus may develop. Project Roles:
D. Kwon (), B. Kwun (), J. Ahn (), D. Lee (), H. Kim ()