Developmental venous anomalies (venous malformations)
A developmental venous anomaly is a dilated (widened) vein, a cluster of dilated veins, or a vein that takes an unusual course. Some doctors might call them venous malformations or venous angiomas.
What causes developmental venous anomalies?
We do not know what causes developmental venous anomalies or exactly how common they are. This is largely because, if they are discovered in adulthood, they very rarely seem to cause any problems for the people with them.
Developmental venous anomalies are sometimes associated with a nearby cavernous malformation which might be the cause of any symptoms.