Angiographically Occult Cerebral Vascular Malformations

Kim, Ill Man; Yim, Man Bin; Kim, Sang Pyo; Lee, Jang Chull; Son, Eun Ik; Kim, Dong Won; Kim, In Hong

Abstract

In order to obtain more accurate pathological diagosis of the angiographically occult vascular malformations(AOVM) of the brain in the future and to examine the clinical, and radiological characteristics and management outcome of the AOVM, the authors retrospectively reviewed the 30 cases of AOVM in which patients were treated at our instituition during the past 11-year period. The pathological specimens were reexamined, and the lesions were reclassified according to the strict histopathological criteria. The clinical characteristics, radiological features, the difference between the clinical and pathological diagnosis and the management results were studied. There were 15 males and 15 females. The mean age at the time of diagnosis was 31 years, ranging from 3 months to 74 years. The clinical diagnosis were arteriovenous malformation(AVM) in 18 cases, cavernous angioma in 11 and mixed lesion in 1. The pathologic diagnosis was AVM in 14 cases, cavernous angioma in 2, and unclassified lesion in 12. The common presenting symptoms were hemorrhage(53.3%), seizure(20.0%) and mass lesions(20.0%). Twenty four lesions were located at the supratentorial region, 4 at cerebellum and 2 at pons. Most of the lesions were revealed as high density masses with minimal or no contrast enhancement on CT and a core of mixed signal intensity with a peripheral low signal intensity rim on T2-weight MRI. Preoperative clinically significant recurrent hemorrhages were noted in 8 cases and one of them showed marked deterioration of the neurological functions a result of recurrent hemorrhage. Twenty-eight patients underwent surgery and all except one improved neurologically. Six patients initially presented with seizure showed improvement in seizure frequency after operation. One patient who had the lesion at the pons was managed by a radiosurgery and one patient who refused surgery was managed by a conservative method. The conservatively managed patient and another patient who was not found AVM at the hematoma cavity during initial operation rebled about 2 years later following diagnosis and surgery. Thse findings suggest that the complete microsurgical excision, which prevents rebleeding and suppresses seizure activity, represents the treatment of choice for patients with clinically symptomatic AOVM. Avoiding the injury of the vascular mass, obtaining sufficient biopsy specimen during surgery, together with careful histopathological observation of operative specimens through complete clinical-radiological-pathological context are necessary to obtain more accurate pathological diagnosis.