Specific Types & Syndromes
Benign enlargement of the subarachnoid spaces (BESS)
Benign enlargement of the subarachnoid spaces is another term for benign external hydrocephalus, describing widened fluid spaces around an infant's brain.
In short: Benign enlargement of the subarachnoid spaces (BESS)
- It is another name for benign external hydrocephalus.
- It describes widened fluid spaces around the brain in infants.
- It is typically benign and self-resolving.
- It is associated with a larger-than-average head.
What it is
Benign enlargement of the subarachnoid spaces (BESS) is an alternative term for benign external hydrocephalus, describing the widened CSF-filled spaces around the brain seen in some infants. It refers to the same generally benign condition.
Understanding Benign enlargement of the subarachnoid spaces (BESS)
BESS (also called benign extra-axial fluid of infancy, among other names) describes prominent subarachnoid spaces over the brain, typically without raised pressure, associated with a large head and often a family history of large heads. Like benign external hydrocephalus, it usually resolves on its own as the child grows, and many affected children develop normally. The variety of names for this condition can be confusing, but they describe the same generally benign finding. Doctors monitor head circumference and development and use imaging to confirm the benign nature.
Why it matters
Understanding that BESS and benign external hydrocephalus are the same helps families read records consistently and recognize this common, generally benign infant finding, while monitoring continues.
Common questions
Is BESS the same as benign external hydrocephalus?
Yes — they describe the same condition.
Where is the fluid?
In the subarachnoid spaces around the brain.
Is it usually serious?
No — it is typically benign and self-resolving.
Bottom line
Benign enlargement of the subarachnoid spaces is another term for benign external hydrocephalus, a generally benign infant condition.
Browse all 265 Hydrocephalus definitions
Read the Hydrocephalus patient guides
Not sure which page you need? Put words to it with the symptom navigator