Pathological changes in surgically resected angiographically occult XXXX after radiation.

@entity1 @entity410 @entity82 @entity2758 @entity548 @entity39 @entity75 @entity1462
OBJECTIVE: The goal of this study was to evaluate the pathological changes associated with radiation treatment (stereotactic radiosurgery or conventional irradiation) of angiographically occult @entity1462 (AOVMs). METHODS: Eleven @entity1 underwent surgical resection of an AOVM in the mesial temporal lobe, brain stem, thalamus, or basal ganglia after previous radiation treatment. The indications for surgery were recurrent symptomatic @entity548 from the lesion in 10 @entity1 and recurrent intractable @entity410 in 1 @entity1 . Radiation was used as the initial therapy because the risk of surgical resection was deemed too high. Three @entity1 received conventional radiation therapy of 3000 to 5400 rads at an outside institution. One @entity1 received radiosurgery with the gamma knife at another institution using a dose of 15 Gy to the margin. The remaining 7 @entity1 received stereotactic radiosurgery with a helium-ion particle beam. The dose range was from 18 to 26 Gy equivalents. The interval from radiation to surgical resection ranged from 1 to 10 years, with a mean of 3.5 years. These lesions were compared with 10 nonirradiated cavernous malformations. RESULTS: One @entity75 was identified pathologically as a true @entity2758 despite being angiographically occult. This lesion did not demonstrate significant changes in the vasculature but did have radiation @entity39 of the surrounding brain 5 years after 25 Gy equivalents of helium-ion radiosurgery. Two other specimens were too small to identify the type of @entity1462 adequately. Of the remaining eight malformations identified as cavernous malformations, six showed a combination of marked @entity82 of the vascular channels, @entity39 , and ferrugination. However, the @entity39 was the only finding unique to the @entity75 compared with nonirradiated controls. All the @entity75 still had patent vascular channels; none were completely thrombosed. CONCLUSION: Radiosurgery or conventional radiation therapy did not cause histologic vascular obliteration in intracranial AOVMs evaluated 1 to 10 years (mean 3.5 yr) after radiation delivery. It should be recognized that these @entity1 are irradiation failures who may not be representative of all irradiated @entity1 . However, recurrent @entity548 from AOVMs may relate to poor radiation response in some @entity1 .
