Outcome of Fetuses with Supratentorial Extra-Axial Intracranial Cysts: A Systematic Review

Staged neurosurgical approach for giant and progressive neonatal arachnoid cysts: a case series and review of the literature

OBJECTIVES

Prenatally diagnosed complex arachnoid cysts are very rare. While the true prenatal incidence is still unknown, they account for approximately 1% of intracranial masses in newborns. They rarely exhibit rapid growth or cause obstructive hydrocephalus, but if they increase to such a dimension during pregnancy, the ideal management is not well established. We present our detailed perinatal experience, covering prenatal diagnosis, a compassionate delivery process, and neonatal stabilization. Finally, a thorough postnatal neurosurgical intervention was performed. Initially, our focus was on the gradual reduction of cyst size as a primary effort, followed by subsequent definitive surgical treatment.

METHODS

This case series shows the treatment course of three fetuses with antenatally diagnosed large arachnoid cysts. We present pre- and postnatal management and imaging, as well as the surgical treatment plan and the available clinical course during follow-up.

RESULTS

Two girls and one boy were included in the current review. All three cases presented with prenatally diagnosed complex arachnoid cysts that increased in size during pregnancy. The mean gestational age at delivery was 35 weeks (range 32 to 37 weeks), and all patients were delivered by a caesarian section. Increasing head circumference and compression of brain structures were indications for delivery, as they are associated with a high risk of excess intracranial pressures and CSF diapedesis, as well as traumatic delivery and maternal complications. All cysts were supratentorial in location; one expanded into the posterior fossa, and one was a multicompartment cyst. All children underwent an initial surgical procedure within the first days of life. To relieve cyst pressure and achieve a reduction in head circumference, an ultrasound-guided or endoscopic-assisted internal shunt with drainage of the cyst to the ventricles or subdural/subarachnoid space was inserted. Definite surgical therapy consisted of cyst marsupialization and/or cysto-peritoneal shunt implantation. All children survived without severe neurodevelopmental impairments.

CONCLUSION

With the cases presented, we demonstrate that the slow reduction of immense cyst size as an initial procedure until optimal requirements for final surgical treatment were achieved has proven to be optimal for neurological outcome. Special emphasis has to be taken on the delicate nature of premature newborn babies, and surgical steps have to be thoroughly considered within the interdisciplinary team.

Ultrasound and magnetic resonance imaging features of fetal intracranial cystic lesions: A pictorial essay

This pictorial essay focuses on ultrasound (US) and magnetic resonance imaging (MRI) features of fetal intracranial cysts. Intracranial cysts are common findings in prenatal imaging, and if great attention is paid to their size, location, and imaging features, they can be diagnosed accurately. They are usually detected by fetal ultrasound exams. However, when ultrasound data on cystic lesion characteristics is insufficient, MRI and fetal neurosonogram are the best options for detecting other associated anomalies. The prognosis is highly dependent on their location and whether they are associated with other fetal anomalies.

Value of pre- and postnatal magnetic resonance imaging in the evaluation of congenital central nervous system anomalies

Fetal MRI and neonatal MRI of the central nervous system (CNS) are complementary tools that can help to accurately counsel and direct the management of children with anomalies of the central nervous system. Postnatal MRI can add to fetal MRI by allowing for monitoring of changes in the severity of disease, better delineation of a suspected prenatal anomaly, evaluation for secondary pathologies related to the primary diagnosis, and surgical management direction. In this review we discuss the roles of fetal and neonatal MRI in the diagnosis and treatment of congenital anomalies of the CNS through a series of case examples and how both are important in patient management.

The Significance of Fetal Brain Ventricular Asymmetry Without Dilation

OBJECTIVES

Fetal brain non-dilated ventricular asymmetry (NDVA) is a common finding on prenatal ultrasound exams. However, the optimal prenatal management in these cases remains unknown. We aimed to evaluate the benefit of prenatal genetic and magnetic resonance imaging (MRI) exams performed in cases of fetal NDVA detected on ultrasound.

METHODS

A historical cohort study from a tertiary medical center. Singleton pregnancies with fetal brain NDVA diagnosed on ultrasound were included. We defined ventricular asymmetry as a difference of ≥2.0 mm between the lateral ventricles and ventricular dilation as ventricular width of >10.0 mm. Outcomes were evaluated with genetic exams (karyotype and chromosomal microarray analysis [CMA]) and fetal brain MRI.

RESULTS

During the study period, there were 145 cases diagnosed with NDVA on ultrasound that comprised the cohort study. The rate of abnormal karyotype was 1.8% (1/56) and of abnormal CMA was 10% (3/30). The rate of minor additional CNS findings did not differ between ultrasound and MRI (3.4 versus 2.8%, respectively, p = .74). No major additional fetal brain findings were detected on MRI performed after ultrasound.

CONCLUSIONS

In cases diagnosed with NDVA on ultrasound, no significant additional anomalies were detected on fetal brain MRI. The rate of abnormal genetic tests was relatively high and warrants further studies.

Normal cavum veli interpositi at 14-17 gestational weeks: three-dimensional and Doppler transvaginal neurosonographic study

OBJECTIVES

To provide evidence to support the hypothesis that the midline cyst-like fluid collection that is frequently observed on fetal brain ultrasound (US) imaging during the early second trimester represents a normal transient cavum veli interpositi (CVI).

METHODS

This was a retrospective analysis of 89 three-dimensional normal fetal brain volumes, acquired by transvaginal US imaging in 87 pregnant women between 14 and 17 gestational weeks. The midsagittal view was studied using multiplanar imaging, and the maximum length of the fluid collection located over (dorsal to) the tela choroidea of the third ventricle was measured. We calculated the correlation of the transverse cerebellar diameter (TCD) and of the maximum length of the fluid collection with gestational age according to last menstrual period. Color Doppler images were analyzed to determine the location of the internal cerebral veins with respect to the location of the fluid collection. Reports of the second-trimester anatomy scan at 22-24 weeks were also reviewed.

RESULTS

Interhemispheric fluid collections of various sizes were found in 55% (49/89) of the volumes (mean length, 5 (range, 3.0-7.8) mm). There was a strong correlation between TCD and gestational age (Pearson's correlation, 0.862; P < 0.001). There was no correlation between maximum fluid length and gestational age (Pearson's correlation, -0.442; P = 0.773). Color Doppler images were retrieved in 32 of the 49 fetuses; in 100% of these, the internal cerebral veins coursed within the echogenic roof of the third ventricle. The midline structures were normal at the 22-24-week scan in all cases.

CONCLUSIONS

In approximately half of normal fetuses, during the evolution of the midline structures of the brain, various degrees of fluid accumulate transiently in the velum interpositum, giving rise to a physiologic CVI. Patients should be reassured that this is a normal phenomenon in the early second trimester that, if an isolated finding, has no influence on fetal brain development. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

The curious incident of a cavum velum interpositum cyst in twins of a mother carrying May-Hegglin anomaly: a case report and short literature review

Background

May-Hegglin anomaly is an autosomal dominant inherited condition, characterized by thrombocytopenia, giant platelets and Dohle-like bodies. Incidence is unknown and affected individuals can show from mild to moderate-severe haemorrhagic symptoms. The cyst of cavum veli interpositi (a virtual space filled with fluid within the third ventricle) is rarely reported in the foetal period. Furthermore, it is unclear whether isolated cavum veli interpositi cysts are a normal variant or developmental malformations. The simultaneous presence of these two anomalies was never described.

Case presentation

We describe a very rare case of a twin monochorionic pregnancy in a woman with the May-Hegglin anomaly, whose foetuses carried cavum veli interpositi cysts. Since childhood, our patient had shown macro-thrombocytopenia, deafness and bleeding (epistaxis and menorrhagia), but she was misdiagnosed until the age of 30 years when our Centre identified a de novo allelic variant in the gene MYH9 coding for the non-muscle myosin heavy chain IIa. Our patient bled neither during the pregnancy, nor in the peripartum period. Children are now eight-months-old and have never bled, although both inherited the MYH9 variant and have thrombocytopenia with giant platelets. Furthermore, none of them developed psychomotor disorders.

Conclusions

To the best of our knowledge, this is the sixth case of twin pregnancy in a woman carrying May-Hegglin anomaly and the first one with cavum veli interpositi cysts in the neonates. We speculate that MYH9 could have, at least in part, played a role in the development of both conditions, as this gene has a pleiotropic effect.

Cavum velum interpositum cysts in normal and anomalous fetuses in second trimester of pregnancy: Comparison of its size and prevalence

OBJECTIVE

Cavum veli interpositi (CVI) is a potential space below the splenium of corpus callosum and sometimes presents as a cyst.

MATERIALS AND METHODS

In this prospective cross-sectional study, 360 fetuses with normal second trimester scan and 152 s trimester fetuses with structural abnormalities were included.

RESULTS

The CVI cysts were more common in fetuses with brain anomaly compared to normal fetuses and fetuses with extra-central nervous system (CNS) anomalies (23% vs 18.3% and 18% respectively; p value < 0.01). The mean size of cysts in normal fetuses, fetuses with extra-CNS anomalies and fetuses with brain abnormalities was 4.6 mm, 5.8 mm and 9.2 mm respectively. There was a significant difference between cysts size in normal fetuses and fetuses with brain anomalies (p value < 0.01) and the cut-point was 7.1 mm.

CONCLUSION

The prevalence of CVI cysts is more in fetuses with brain anomaly. Fetuses with a cyst size >7.1 mm need a more detailed brain examination.

Prenatal diagnosis of arachnoid cysts: a case series and systematic review

INTRODUCTION

Primary cysts are believed to arise from the splitting of the arachnoid membrane during prenatal development and can be diagnosed in utero. Prenatal diagnosis is uncommon; therefore, the evidence base for counselling expectant mothers is limited. The purpose of this article is to present a case series and review the current literature on prenatally diagnosed arachnoid cysts.

METHOD

A keyword search of hospital electronic records was performed for all patients with a prenatally diagnosed arachnoid cyst at a tertiary neurosurgical centre. Case notes were reviewed for all patients diagnosed between 2005 and 2017. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to structure a systematic review of all English language articles published up to May 2018.

RESULTS

A total of eight eligible patients were identified from our own records and 123 from the literature. Sixty-eight per cent of patients had a normal outcome. Sixty-three per cent of patients underwent surgical intervention which was not associated with abnormal outcome. The diagnosis of syndromic/genetic diagnosis (p < 0.001) and the presence of other intra-cranial anatomical abnormalities (p = 0.05) were significant predictors of abnormal outcome.

CONCLUSION

The pathogenesis and prognosis of a prenatal arachnoid cyst diagnosis remain unclear. These results suggest favourable outcomes from simple cysts without associated abnormalities and expectant mothers should be counselled accordingly. A wider prospective review is required to better established evidence-based practice.