Síndrome PHACES (Pascual Castroviejo tipo II): resonancia magnética pre y posnatal

Fetal neuroimaging findings in PHACE syndrome: case report and review of the literature

OBJECTIVE

To describe the main prenatal sonographic and magnetic resonance imaging (MRI) features leading to the diagnosis of Posterior fossa malformations, Hemangiomas of the face, Arterial anomalies, Coarctation of the aorta and cardiac defects, and Eye abnormalities (PHACE) syndrome. The literature was also reviewed in order to determine the main neuroimaging features of fetuses with this condition.

RESULTS

The index case was referred at 24 weeks' gestation with the probable diagnosis of Dandy-Walker malformation. Prenatal sonographic examination revealed hypoplasia of the left cerebellar hemisphere, hypoplasia of the cerebellar vermis, and enlarged cisterna magna (the "tilted telephone receiver sign"). Fetal MRI at 30 weeks confirmed the findings and also revealed an ipsilateral retrocerebellar cyst communicating with the asymmetrical dilated fourth ventricle, upward displacement of the left cerebellar hemisphere, and elevation of the ipsilateral tentorium. Postnatally, a large left facial segmental hemangioma as well as ipsilateral vascular intracranial malformations were identified, confirming the diagnosis of PHACE syndrome. A review of the literature revealed 11 reports describing 22 fetuses with prenatal imaging studies, including ours, confirming the high prevalence of specific posterior fossa abnormalities associated with PHACE syndrome.

CONCLUSION

Our case and those reported in the literature support the observation that PHACE syndrome presents with characteristic features affecting the posterior fossa, which can be identified through prenatal sonography and fetal MRI.

The cerebellar "tilted telephone receiver sign" enables prenatal diagnosis of PHACES syndrome

OBJECTIVES

To describe a unique posterior fossa neuroimaging characteristic of prenatal PHACES syndrome (PS): unilateral cerebellar hypoplasia (UCH) and ipsilateral posterior fossa (PF) cyst communicating with an asymmetrically distended 4th ventricle.

METHODS

The registries of seven prenatal diagnosis centers were searched for cases with PF findings and a postnatal diagnosis of PS. All records were evaluated for ultrasound and MRI findings and the postnatal outcome. PS was diagnosed after birth according to the consensus statement on diagnostic criteria for PS from 2009. The imaging findings of the PS fetuses were compared to a group of consecutive cases with fetal UCH, whose postnatal diagnosis was not PS.

RESULTS

The PS group included 10 fetuses. All were referred due to UCH accompanied by an ipsilateral retrocerebellar cyst. All pregnancies resulted in livebirths, all newborns had a large segmental facial hemangioma. In all PS fetuses the affected cerebellar hemisphere was upwardly displaced by an ipsilateral PF cyst communicating with an asymmetrically distended 4th ventricle. An upwardly rotated and deviated vermis merged with the contralateral cerebellar peduncles forming an elongated oblique connection between the cerebellar hemispheres, resulting in a unique cerebellar shape, "a tilted telephone receiver sign" (TTRS), on the coronal plane through the upper vermis.The non-PS group included 11 fetuses with UCH: clastic cerebellar lesions (8) and a unilateral PF arachnoid cyst (3). The TTRS was not depicted in any of them (p < 0.0005).

CONCLUSIONS

The cerebellar TTRS is a specific fetal imaging feature of PHACES syndrome enabling its prenatal diagnosis.

Soft-tissue vascular malformations and tumors. Part 1: classification, role of imaging and high-flow lesions

Vascular malformations and tumors, also known as "vascular anomalies", comprise an extensive variety of lesions involving all parts of the body. Knowledge of their classification and imaging characteristics is paramount. Whereas hemangiomas are benign vascular tumors, characterized by cellular proliferation and hyperplasia; vascular malformations are not real tumors and characteristically exhibit normal endothelial turnover. Vascular malformations are classified according to the predominant vascular channel as arterial, capillary, venous, lymphatic, or mixed. Ultrasound and MRI are the main imaging modalities used in the diagnosis and classification of the vascular anomalies. In this series of two articles we review the classification of vascular anomalies, describe the role of imaging, summarize their distinctive histopathogenic, clinical and imaging features, and discuss the treatment options. On the first article we discuss the high-flow lesions, whereas the slow-flow lesions will be reviewed on the second. Complex syndromes with associated vascular tumors and malformations will be also presented.

Evaluation of the fetal cerebellum by magnetic resonance imaging

Obstetric protocols dictate that the fetal cerebellum should always be assessed during sonograms during pregnancy. For various reasons, including technical limitations or inconclusive sonographic findings, suspicion of cerebellar abnormalities is one of the most common indications for prenatal magnetic resonance imaging (MRI). Although sonography is the imaging technique of choice to assess the cerebellum, MRI shows the anatomy of the posterior fossa and abnormalities in the development of the fetal cerebellum in greater detail and thus enables a more accurate prenatal diagnosis. We describe and illustrate the normal anatomy of the fetal cerebellum on MRI as well as the different diseases that can affect its development. Moreover, we review the most appropriate terminology to define developmental abnormalities, their differential diagnoses, and the role of MRI in the prenatal evaluation of the posterior fossa.

Prenatal unilateral cerebellar hypoplasia in a series of 26 cases: significance and implications for prenatal diagnosis

OBJECTIVE

To define imaging patterns of unilateral cerebellar hypoplasia (UCH), discuss possible pathophysiological mechanisms and underline the etiology and prognosis associated with these lesions.

METHODS

In this retrospective study we reviewed the charts of 26 fetuses diagnosed between 2003 and 2011 with UCH, defined by asymmetrical cerebellar hemispheres with or without decreased transverse cerebellar diameter. The review included analysis of the anatomy of the cerebellar hemispheres, including foliation, borders and parenchymal echogenicity, and of the severity of the hypoplasia. Data from clinical and biological work-up and follow-up were obtained.

RESULTS

Our series could be divided into two groups according to whether imaging features changed progressively or remained constant during follow-up. In Group 1 (n = 8), the progression of imaging features, echogenic cerebellar changes and/or hyposignal in T2*-weighted MR images were highly suggestive of ischemic/hemorrhagic insult. In Group 2 (n = 18), imaging features remained constant during follow-up; UCH was associated with abnormal foliation in three proven cases of clastic lesions, a cystic lesion was noted in three cases of PHACE (posterior fossa anomalies, hemangioma, arterial anomalies, cardiac abnormalities/aortic coarctation, eye abnormalities) syndrome and, in the remaining cases, UCH remained unchanged, with no imaging pattern typical of hemorrhage. In 24 cases the infant was liveborn and follow-up was continued in 23, for a mean period of 3 years. Among these, neurological complications were identified in seven (in one of seven (at a mean of 46 months) in Group 1 and in six of 16 (at a mean of 35 months) in Group 2). The surface loss of cerebellar hemisphere was > 50% in 19/24 fetuses and the vermis was clearly normal in appearance in 19/24. Predisposing factors for fetal vascular insult were identified in eight cases: these included maternal alcohol addiction, diabetes mellitus, congenital cytomegalovirus infection and pathological placenta with thrombotic vasculopathy and infarctions.

CONCLUSION

UCH is defined as a focal lesion of the cerebellum that may be secondary to hemorrhage and/or ischemic insult, suggesting a clastic origin, particularly when imaging follow-up reveals changes over time. UCH may also be a clue for the prenatal diagnosis of PHACE syndrome. The amount of surface loss of cerebellar hemisphere does not correlate with poor prognosis. UCH with normal vermis is often associated with normal outcome.