Objective: Once thought to be rare entities, mixed cerebrovascular malformations with pathological features of more than one type of malformation within the same lesion are now being recognized with increasing frequency. Their identification generates several hypotheses about common pathogenesis or causation-evolution among different types of lesions and leads to controversial discussion on therapeutic strategies.
Methods: Fifteen patients drawn from a consecutive series of 58 patients harboring cavernous malformations (25.9%) were found to have an associated venous malformation (VM). Three (33.3%) of the first 9 patients, in whom the large draining vein of the VM had been left untouched at previous interventions, developed recurrent and/or de novo lesions.
Results: Histopathological analysis, interestingly, revealed that the new lesions were different in nature (three arteriovenous angiomas in two patients, a capillary telangiectasia in one patient). During extirpation of the new malformation, the draining vein of the VM in these three patients could be coagulated without any adverse events. Coagulation and dissection of the draining vein of the associated VM was performed in six more patients of our series, and this has prevented development of new lesions up to now.
Conclusion: Our results are in favor of the hypothesis that the draining vein of a VM is the actual underlying abnormality of mixed vascular malformations. Causing flow disturbances and having the potential for hemorrhages, the VM seems to promote the development of new adjacent malformations. Thus, permanent cure of associated malformations might depend on the surgical treatment of the VM. We present a preliminary personal series and a thorough review of the literature.