A case of developing obstructive hydrocephalus following aqueductal stenosis caused by developmental venous anomalies.

Developmental venous anomalies (DVAs), previously also known as venous angiomas, are variations of normal trans-medullary veins draining from white and gray matter. DVAs are usually asymptomatic and mostly discovered incidentally on brain imaging. However, some studies have reported symptomatic cases associated with DVAs. In this report, we report an extremely rare case of a 14-month-old boy with obstructive hydrocephalus following aqueductal stenosis caused by developmental venous anomalies. At the age of 14 months, his head circumference exceeded + 2SD significantly. Brain magnetic resonance imaging (MRI) showed triventriculomegaly and dilated collector vein coursing through the Sylvian aqueduct, causing aqueductal stenosis. Endoscopic third ventriculostomy (ETV) was successfully performed. During the procedure, a dilated collector vein was confirmed obstructing the Sylvian aqueduct. Postoperative cine MRI showed good flow signal through the opening and improvement of hydrocephalus was noted. Obstructive hydrocephalus following aqueductal stenosis caused by DVAs is very rare; nonetheless, it can be considered as a causal differential diagnosis for hydrocephalus. Whether ETV should be chosen, as the technique for diversion of cerebrospinal fluid (CSF) flow, remains controversial. This case report showed that ETV was effective and safe.