Developmental venous anomaly (DVA), also know as venous angioma, represents a dilated cerebral vein which is a collector for other smaller veins; it is considered a persistent embryonal vein.
Most authors agree than DVAs are normal vein but in unusual place, so they are required for normal venous outflow and resection of them should be avoided, because in most cases would lead to the venous infarction.
This case represents combined subarachnoid hemorrhage (SAH) and venous infarction due to thrombosis of DVA in hindbrain. Coexistence of SAH and venous infarction of such etiology are rare, to our knowledge this is the first case, because we couldn't identify similar cases in english literature.
Since this case demonstrates development of venous infarction after DVA thrombosis, one may consider this a proof for requirement of DVA patency for normal venous outflow and need for avoiding DVAs resection.
The differential diagnosis for the case is pontine arterial infarction due to vasospasm and delayed cerebral ischemia, that is frequent after 3-10 days in patients with SAH, but lack of restricted diffusion in brainstem lesions makes arterial stroke possibility unlikely.