Benign enlargement of subarachnoid spaces (BESS) in infancy:

Nahid Khosroshahi, Ali Nikkhah




Macrocephaly are among the most frequent reasons for referral to a pediatric neurologist.

Benign enlargement of subarachnoid spaces (BESS) in infancy is a most common cause of macrocephaly and is characterized by excess cerebrospinal fluid (csf) in the subarachnohd spaces.

In this review, we described epidemiology, etiology, clinical presentation, pathogenesis, neuroimaging, treatment and outcome of entity from current literature.

Materials & Methods

We searched the related papers in electronic databases such as Google Scholar, PubMed, and Scopus .

Key words for searching were benign enlargement of subarachnoid spaces in infancy, external hydrocephaly and neuroimaging.


The related data focusing on the etiology, epidemiology, clinical presentation, differential diagnosis, neuroimaging, treatment and outcome with emphasis on diagnostic work up were gathered and described.


BESS is most common cause of macrocephaly in infancy . It is characterized dy macrocephaly , excess csf in subarachnoid spaces and normal ventricles or mild ventricolomegaly.  Self-limited disorder in infancy ,mostly in  male and  with familial tendency  and normal or  mildly delay motor or language delay.

Mostly favorable  prognosis without need  treatment.

Neuroimaging is essential for diagnosis and selection of useful tool  and close observation of patient is necessary  and sufficient for follow up. It is best way from economic points and reduce hazards of inappropriate  neuroimaging.


Benign enlargement of subarachnoid space, Benign external hydrocephaly, Neuroimaging

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