Developmental venous anomaly as a rare cause of obstructive hydrocephalus

Developmental venous anomalies (DVA), previously known as cerebral venous malformations or venous angiomas, are common benign entities often incidentally discovered at MRI examinations. They are non‑pathologic variants of normal deep parenchymal veins that are usually asymptomatic, but they can rarely cause some complications. In this paper we described a rare case of obstructive hydrocephalus caused by a DVA located within the cerebral aqueduct and we also reviewed the previous literature on this topic. A 37‑year‑old man was diagnosed with symptomatic tri‑ventricular hydrocephalus that during the last year caused episodes of ictal headaches accompanied by vertigo, diaphoresis and lipothimic events. The MRI and the angiography showed the presence of a large collector vein coursing within the aqueduct, which was part of a complex DVA in the posterior fossa, responsible for the aqueductal stenosis and obstructive hydrocephalus. The patient was submitted to endoscopic third ventriculostomy (ETV) and then he had a complete resolution of symptoms. A literature review was performed through Medline Pubmed on papers published in English from 1937 to 2015 with the following key words: DVA, obstructive hydrocephalus, acqueductal stenosis, venous angioma, venous malformation, medullary malformation. Including our case, the literature research identified 16 reports in the Medline database for 18 patients presenting with obstructive hydrocephalus caused by a DVA including our case. In approximately 60% (10/17) of cases, the stenosis causing obstructive hydrocephalus was present in the cerebral aqueduct. The floor of the IV ventricle and the third ventricle were the second most common locations and DVAs were identified in 20% of cases (3/17) for each of these regions. In the remaining case the venous malformation was found in the Foramen of Monro. Clinical presentation before diagnosis lasted on average 23 months ranging from 1 month to 7 years. The mean age at diagnosis was 27 (range 3 days- 58 years). The most common presenting symptom was persistent headache, representing a major complaint in 80% of cases (12/15). In 78% (14/18) of cases MRI was crucial in the diagnosis. ETV was performed in 47% (8/17) of patients, whereas no treatment or clinical follow‑up was required in 18% (3/17) and VP Shunt in 12% (2/17) of cases. Instead, VA shunt, transcallosal approach and acqueductal stenting were performed in one patient each, corresponding singularly to 6% (1/17) of all cases. Despite the fact that DVAs are asymptomatic, they may rarely cause obstructive hydrocephalus because of impairment in the CSF flow. They should be considered in the differential diagnosis of any patient presenting with obstructive hydrocephalus. ETV has been demonstrated as an effective treatment option in the management of obstructive hydrocephalus due to a DVA.