Cavernous angiomas (cavernomas)

Cavernomas are vascular malformations with well-defined margins and a surrounding haemosiderin deposit, but no angiographically demonstrable lesion. Often these are asymptomatic lesions that require no therapy. Recurrent bleeding or other symptoms may be cured by surgical excision if they are easily accessible but frequently they are not. Two large series have established radiosurgery as the optimal therapy. Kondziolka et al. (5) reported 47 patients with bleeding cavernomas and noted a significant reduction in risk of bleeding from 32% per year to 9% per year. Kida et al. (6) analysed 51 cases presenting either as haemorrhage or intractable epilepsy. Haemorrhage was controlled in 86% and epilepsy was controlled in 64%. Permanent complications were 5%. The complication rate for radiosurgical treatment of cavernomas is unexpectedly high and this has been attributed to an amplification or radiosensitisation effect caused by the haemosiderin ring (7). For this reason doses should be less than for AVM of the same size and the haemosiderin ring should be excluded from the treatment plan.

REFERENCES

1. Karlsson B. Gamma knife surgery of cerebral arteriovenous malformations. Thesis, Karolinska Institute, Stockholm 1996.
2. Pollock BE. Patient outcomes after arteriovenous malformation radiosurgery. In Lunsford LD, Kondziolka D, Flickinger JC (eds) Gamma knife brain surgery. Prog Neurol Surg, Basel, Karger 1998; 14: 51-59.
3. Chang JH, Chang JW, Park YG et al. Factors related to complete occlusion of arteriovenous malformations after gamma knife surgery. J Neurosurg 2000; 93 (suppl 3): 96-101.
4. Chang SD, Marcellus ML, Marks MP et al. Multimodality treatment of giant intracranial arteriovenous malformations. Neurosurgery 2003; 53: 1-13.
5. Kondziolka D, Lunsford LD, Flickinger JC et al. Reduction of haemorrhage risk after stereotactic radiosurgery for cavernous malformations. J Neurosurg 1995; 83: 825-831.
6. Kida Y, Kobayashi T, Tanaka T. Radiosurgery of symptomatic angiographically occult vascular malformations with gamma knife. In Kondziolka D (ed), Radiosurgery, Basel, Karger 1995; 1:207-217.
7. St George EJ, Perks J, Plowman PN. Stereotactic radiosurgery XIV: the role of the haemosiderin ‘ring’ in the development of adverse reactions following radiosurgery for intracranial cavernous malformations: a sustainable hypothesis. Br J Neurosurg 2002; 16: 385-391.