Dural sinus malformation (DSM) in fetuses. Diagnostic value of prenatal MRI and follow-up.

Dural sinus malformations (DSM) are rare malformations mainly reported after birth. The objectives of this study are to describe their prenatal patterns and to focus on their possible favorable outcome. This multicenter retrospective study reported 13 cases of DSM prenatally diagnosed. The admission criterion was a dural mass posterior to the vermis. In 12 patients, MRI was performed after US. Follow-up in 10 born babies (mean: 8 months) and three neuropathological examinations were available. In all fetuses, DSM presented as a well-delimited round mass involving the torcular. The follow-up examinations (n = 10) revealed progressive thrombosis of the DSM marked by a heterogeneous pattern (US and MRI) with concentric rings. The volume of the mass decreased, with complete regression in seven patients (five before and two after birth). One child died at the age of 5 months in the context of major hydrocephalus and another developed atrophy of the frontal lobes. The eight other babies were doing well (5 days to 3 years) without any treatment (n = 6) or following treatment for hydrocephalus (n = 2). Prenatal DSM may have a typical MR pattern, and the prognosis might not be as bad as has previously been reported. In the absence of criterion to predict the hydrovenous cerebral imbalance, it is mandatory to check the parenchyma and the ventricles during the pregnancy.