Prenatal Diagnosis of Dilated Cavum Septum Pellucidum et Vergae

Abstract

The cavum septum pellucidum is a fluid-filled cavity located between the membranes of the septi pellucidi, which should always be visualized sonographically in normal fetuses between 18 and 37 weeks gestation and in approximately 50% of term infants. The cavum vergae, a cavity within the septum pellucidum, is located posterior to an arbitrary vertical plane formed by the columns of the fornix. We present a case in which markedly dilated cavum septum pellucidum et vergae noted at 29 weeks gestation was associated with midgut malrotation and volvulus, and review the literature pertaining to this unusual prenatal ultrasonographic diagnosis.

Sonographic appearance of the cavum septum pellucidum et vergae in normal fetuses in the second and third trimesters of pregnancy

“…Fetal CSPVs in association with pathologic cerebral findings have been documented by case report, often with dilation of CV. In one report, the CSPV was associated with hydrocephalus and gut malrotation, where the CSP width was 12.6 mm, and the CV width, although not directly measured, appeared to be greater than 10 mm on axial US view . In another case report of three fetuses with dilated CVs, the first had associated ventriculomegaly, and the second showed raised intracranial hypertension considered to be a result of a dilated CV .…”

“…The CSPV is considered to be a normal variant of the CSP; however, it may be mistaken for pathologies of similar US appearance such as an intracranial cyst . The CSPV may be found in up to 30% of newborns, and it is rarely reported with concurrent pathology . Although the US criteria for identifying normal CSPs in fetuses are well established, there is a lack of quantitative measures for defining a normal CSPV .…”

“…7,9 The CSPV may be found in up to 30% of newborns, and it is rarely reported with concurrent pathology. 10,11 Although the US criteria for identifying normal CSPs in fetuses are well established, there is a lack of quantitative measures for defining a normal CSPV. 3,12 In addition, little is known about what percentage of CSPVs are found in the normal fetus.…”

Enlarged Cavum Septi Pellucidi and Vergae in the Fetus: A Cause for Concern

“…In another report of 3 cases looking at midline cystic structures larger than 10 mm diagnosed prenatally as an enlarged cavum vergae, 1 had associated ventriculomegaly and lumbar meningocele; 1 required shunting postnatally for intracranial hypertension; and 1 was asymptomatic . A single report was made of a fetus with a large cavum septi pellucidi and cavum vergae (12.6 mm) who was found to have midgut malrotation postnatally …”

Prenatal Diagnosis of Down Syndrome Associated with Right Aortic Arch and Dilated Septum Cavi Pellucidi

“…Therefore, despite half of prenatally diagnosed vascular rings correspond to RAA/ALSA, only few are chromosomically abnormal. To increase the rarity of this case, the fetus presented a dilated cavum septi pellucidi, a rare malformation [8] undescribed in relation with DS. In this fetus, the cavum was two times the normal measurement, exceeding by far the 2SD limit [9].…”