Venous anomalies and abnormalities of the posterior fossa.

The authors report a series of 16 patients with venous anomalies or abnormalities of the posterior fossa studied by angiography, CT and/or MRI. We believe that so-called venous angiomas are extreme anatomic variants that drain normal territories, and we prefer to call them developmental venous anomalies (DVAs). Posterior fossa DVAs, like the supratentorial ones are classified according to their drainage into deep and superficial types. They are exclusively located in the cerebellum or tectum. In 4 cases DVA was an incidental finding; in 3 an associated cerebral venous malformation (CVM) was found and felt to be the cause of the symptoms; and only in one (with trigeminal pain) was a link between both suspected. Cavernous venous malformations (CVMs) were found in frequent association with DVA (27%). Four cases were single and 2 multiple. Five CVMs were located in the brain stem and 3 in the cerebellum. The clinical and radiological files were reviewed and a direct relationship between symptoms and localization was found in all patients with CVM. In 2 cases venous dysplasia was found: 1 Sturge-Weber and 1 first branchial arch syndrome. Both posterior fossa venous abnormalities were incidental findings.