Fetal MRI of a hypothalamic hamartoma in Pallister-Hall syndrome

Prenatal diagnosis of Pallister-Hall syndrome: ultrasound, magnetic resonance imaging, and three-dimensional reconstructions of phenotypical findings

Pallister - Hall syndrome is a rare malformation that involves the presence of a suprasellar hamartoma and associated malformations. Prenatal diagnosis is also rare, and few cases have been reported using magnetic resonance imaging (MRI). A 35-year-old G5P2A2 woman at the 35th week of gestation was referred to our service. Fetal MRI showed an isointense image in the suprasellar region, pushing the brainstem up and backward, and compressing the vermis and cerebellum on T2-weighted images. On T1-weighted images, the hypointense signal of the tumor was similar to that of the brain parenchyma. Ultrasound images showed a suprasellar mass, which was more echogenic than the normal cerebral parenchyma, posteriorly pushing the brain stem, with involvement of the vermis of the tumor and compression of the posterior fossa. Three-dimensional reconstruction using MRI scan data showed a space view of the tumor and its relationships with the other brain tissues allowing better understanding by parents and multidisciplinary team.

Fetal magnetic resonance imaging in the diagnosis of spinal cord neural tube defects: A prospective study

Objective

This study aimed to evaluate the value of fetal magnetic resonance imaging (MRI) in the prenatal diagnosis of spinal neural tube defects.

Methods

From August 2018 to January 2021, 56 fetuses with suspected spinal cord neural tube defects were treated by prenatal ultrasound in the Neurosurgery Department of the First Medical Center of the People's Liberation Army General Hospital. Fetal MRI was performed within 72 h after ultrasound diagnosis. Forty singleton fetuses were selected. Magnetic resonance examination was performed within 1 month after birth, and the diagnostic coincidence rates of prenatal ultrasound and fetal magnetic resonance examination in the prenatal diagnosis of spinal cord neural tube defects were compared and analyzed using postnatal magnetic resonance examination as the standard.

Results

The coincidence rates of prenatal ultrasound and fetal MRI for the prenatal diagnosis of spina bifida were 71.4% (20/28) and 39.2% (11/28), respectively, and the difference was statistically significant. The coincidence rates of prenatal ultrasound and fetal MRI in the diagnosis of intraspinal lipoma were 52.6% (10/19) and 73.7% (14/19), respectively, and the difference was statistically significant.

Conclusion

Fetal MRI has an advantage over prenatal ultrasound in detecting intraspinal lipoma. Prenatal ultrasound has an advantage over fetal MRI in detecting spina bifida.

Neuroimaging appearance of hypothalamic hamartomas in monozygotic twins with Pallister-Hall syndrome: case report and review of the literature

Background

Pallister-Hall syndrome (OMIM #146510) is a rare autosomal dominant condition caused by a mutation in the GLI3 gene. The cardinal feature of Pallister-Hall syndrome is the presence of hypothalamic hamartomas, which may manifest with seizures, panhypopituitarism and visual impairment. In Pallister-Hall syndrome, dysplastic histogenetic processes responsible for hypothalamic hamartomas are thought to disrupt early craniofacial development. The clinical presentation of Pallister-Hall syndrome may include: characteristic facies (low-set and posteriorly angulated ears, short nose with flat nasal bridge), cleft palate and uvula, bifid epiglottis and laryngotracheal cleft, limb anomalies (e.g., polysyndactyly, short limbs and nail dysplasia), anal atresia, genitourinary abnormalities and congenital heart defects.

Case presentation

We report the case of two monochorionic diamniotic twins diagnosed with Pallister-Hall syndrome during the neonatal period, after the identification of a hypothalamic hamartoma on day 1 by cerebral ultrasound scan, later confirmed by brain magnetic resonance imaging. Cerebral ultrasound and magnetic resonance imaging presentations were identical in both twins.

Discussion and conclusions

We review previously published cases (four reports) of hypothalamic hamartomas identified via cerebral ultrasound and compare reported ultrasonographic features. Main differential diagnoses based on cerebral ultrasound findings are discussed. Full description of typical magnetic resonance imaging appearance is also provided. This is the first case reported in the literature of monochorionic diamniotic twins affected by genetically confirmed Pallister-Hall syndrome with identical hypothalamic hamartomas at cerebral ultrasound and magnetic resonance imaging. Moreover, this paper adds to the existing literature on the sonographic appearance of hypothalamic hamartomas. Considering the consistency in hypothalamic hamartomas’ sonographic appearance, we support the use of cerebral ultrasound as a first-line neuroimaging modality in case of clinical suspicion of Pallister-Hall syndrome.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02618-0.

Pre- and postnatal MR imaging of an asymptomatic giant hypothalamic hamartoma

Hypothalamic hamartomas are rare tumors that are most often diagnosed in early childhood. These lesions are classified as giant hypothalamic hamartomas when they exceed 4 cm in any 1 dimension. The most common presenting symptoms associated with these lesions are precocious puberty, gelastic seizures, and (less commonly) syndromic conditions such as Pallister-Hall syndrome. We present a unique case of an asymptomatic giant hypothalamic hamartoma diagnosed prenatally by fetal magnetic resonance imaging and followed throughout infancy. This case demonstrates the utility of multimetric analysis using difference sequences, including diffuse-weighted imaging, to assess specific properties of intracranial lesions detected in utero and to aid in accurate diagnosis prior to birth.

Surgical treatment of hypothalamic hamartomas

Hypothalamic hamartomas are aberrant masses, composed of abnormally distributed neurons and glia. Along endocrine and cognitive symptoms, they may cause epileptic seizures, including the specific gelastic and dacrystic seizures. Surgery is the treatment of drug-resistant hamartoma epilepsy, with associated positive results on endocrine, psychiatric, and cognitive symptoms. Recently, alternatives to open microsurgical treatment have been proposed. We review these techniques and compare their efficacy and safety. Open resection or disconnection of the hamartoma, either through pterional, transcallosal, or transventricular approach, leads to good epileptological control, but its high complication rate, up to 30%, limits its indications. The purely cisternal peduncular forms remain the only indication of open, pterional approach, while other strategies have been developed to overcome the neurological, endocrine, behavioral, or cognitive complications. Laser and radiofrequency thermocoagulation-based disconnection through robot-guided stereo-endoscopy has been proposed as an alternative to open microsurgical resection and stereotactic destruction. The goal is to allow safe and complete disconnection of a possibly complex attachment zone, through a single intraparenchymal trajectory which allows multiple laser or radiofrequency probe trajectory inside the ventricle. The efficacy was high, with 78% of favorable outcome, and the overall complication rate was 8%. It was especially effective in patients with isolated gelastic seizures and pure intraventricular hamartomas. Stereotactic radiosurgery has proved as efficacious and safer than open microsurgery, with around 60% of seizure control and a very low complication rate. Multiple stereotactic thermocoagulation showed very interesting results with 71% of seizure freedom and 2% of permanent complications. Stereotactic laser interstitial thermotherapy (LiTT) seems as effective as open microsurgery (from 76 to 81% of seizure freedom) but causes up to 20% of permanent complications. This technique has however been highly improved by targeting only the epileptogenic onset zone in the hamartoma, as shown on preoperative functional MRI, leading to an improvement of epilepsy control by 45% (92% of seizure freedom) with no postoperative morbidity. All these results suggest that the impact of the surgical procedure does not depend on purely technical matters (laser vs radiofrequency thermocoagulation or stereotactic vs robot-guided stereo-endoscopy) but relies on the understanding of the epileptic network, including inside the hamartoma, the aim being to plan an effective disconnection or lesion of the epileptogenic part while sparing the adjacent functional structures.

The use of fetal MRI for renal and urogenital tract anomalies

Fetal anomalies are detected in approximately 2% of all fetuses and, among these, genitourinary tract abnormalities account for 30% to 50% of all structural anomalies present at birth. Although ultrasound remains the first line diagnostic modality, fetal MRI provides important additional structural and functional information, especially with the development of faster sequences and the use of functional sequences. The added value of MRI-based imaging is three-fold: (a) improvement of diagnostic accuracy by adequate morphological examination, (b) detection of additional anomalies, and (c) in addition, MRI has the potential to provide information regarding renal function. In this review, we describe the role of fetal MRI in the anatomical evaluation of renal and urogenital tract anomalies, and we also touch upon the contribution of functional MRI to the diagnostic workup of these conditions.

Metabolic, endocrine, and other genetic disorders

Metabolic, endocrine, and genetic diseases of the brain include a very large array of disorders caused by a wide range of underlying abnormalities and involving a variety of brain structures. Often these disorders manifest as recognizable, though sometimes overlapping, patterns on neuroimaging studies that may enable a diagnosis based on imaging or may alternatively provide enough clues to direct further diagnostic evaluation. The diagnostic workup can include various biochemical laboratory or genetic studies. In this chapter, after a brief review of normal white-matter development, we will describe a variety of leukodystrophies resulting from metabolic disorders involving the brain, including mitochondrial and respiratory chain diseases. We will then describe various acidurias, urea cycle disorders, disorders related to copper and iron metabolism, and disorders of ganglioside and mucopolysaccharide metabolism. Lastly, various other hypomyelinating and dysmyelinating leukodystrophies, including vanishing white-matter disease, megalencephalic leukoencephalopathy with subcortical cysts, and oculocerebrorenal syndrome will be presented. In the following section on endocrine disorders, we will examine various disorders of the hypothalamic-pituitary axis, including developmental, inflammatory, and neoplastic diseases. Neonatal hypoglycemia will also be briefly reviewed. In the final section, we will review a few of the common genetic phakomatoses. Throughout the text, both imaging and brief clinical features of the various disorders will be discussed.

Total colonic aganglionosis and imperforate anus in a severely affected infant with Pallister-Hall syndrome

Pallister-Hall syndrome is a complex malformation syndrome characterized by a wide range of anomalies including hypothalamic hamartoma, polydactyly, bifid epiglottis, and genitourinary abnormalities. It is usually caused by truncating frameshift/nonsense and splicing mutations in the middle third of GLI3. The clinical course ranges from mild to lethal in the neonatal period. We present the first patient with Pallister-Hall syndrome reported with total colonic aganglionosis, a rare form of Hirschsprung disease with poor long-term outcome. The patient also had an imperforate anus, which is the third individual with Pallister-Hall syndrome reported with both Hirschsprung disease and an imperforate anus. Molecular testing via amniocentesis showed an apparently de novo novel nonsense mutation c.2641 C>T (p.Gln881*). His overall medical course was difficult and was complicated by respiratory failure and pan-hypopituitarism. Invasive care was ultimately withdrawn, and the patient expired at three months of age. This patient's phenotype was complex with unusual gastrointestinal features ultimately leading to a unfavorable prognosis and outcome, highlighting the range of clinical severity in patients with Pallister-Hall syndrome.

Hypothalamic hamartomas. Part 1. Clinical, neuroimaging, and neurophysiological characteristics

Hypothalamic hamartomas are uncommon but well-recognized developmental malformations that are classically associated with gelastic seizures and other refractory seizure types. The clinical course is often progressive and, in addition to the catastrophic epileptic syndrome, patients commonly exhibit debilitating cognitive, behavioral, and psychiatric disturbances. Over the past decade, investigators have gained considerable knowledge into the pathobiological and neurophysiological properties of these rare lesions. In this review, the authors examine the causes and molecular biology of hypothalamic hamartomas as well as the principal clinical features, neuroimaging findings, and electrophysiological characteristics. The diverse surgical modalities and strategies used to manage these difficult lesions are outlined in the second article of this 2-part review.

Imaging tumors of the pediatric central nervous system

Primary tumors of the central nervous system (CNS) are the second most common neoplasms in children and the leading cause of death in this patient population. The primary objective of this article is to describe the most common pediatric brain tumors and to offer an overview of their respective imaging features, primarily on magnetic resonance imaging. Precise anatomic characterization is essential for developing an appropriate differential diagnosis. Once equipped with this critical information, physicians should be better able to make firm diagnoses, leading to improved disease management and patient outcomes in the setting of CNS tumors of childhood.

Transsphenoidal extension of heterotopic glioneuronal tissue: pathoanatomic considerations in symptomatic neonates

PURPOSE

In this clinical investigation, we aimed (1) to re-evaluate the nature of glioneuronal tissue with transsphenoidal extension and how it fits into the nomenclature of midline malformations and mass lesions; (2) to find out if our imaging findings support current pathoanatomic concepts of clefts and canals in the sphenoid body of newborns.

METHODS

In two neonates with respiratory distress due to nasopharyngeal masses, 3T MRI was performed, and CT in one of them. Imaging features were analyzed in consensus by two pediatric neuroradiologists with histological reports being available. An interdisciplinary panel compared the findings to those of case publications and differential entities from our institutional case collection.

RESULTS

Referring to our rare case of transsphenoidal cerebral heterotopia and unique case of hypothalamic hamartoma with transsphenoidal herniation, glioneuronal heterotopia may definitely extend through the sphenoid bone. Consequently, there is reason for brain heterotopias to be labeled as such also in case of an intracranial component. Connection between heterotopic glioneuronal tissue in the nasopharynx and a hypothalamic hamartoma may go along with indistinct margins to normal brain. Neither extension through a transsphenoidal cleft nor association with a cleft palate are specific for cerebral heterotopia. Our findings support the hypothesis that transsphenoidal cerebral heterotopias do not or at least not invariably follow the route of Rathke's pouch, known as the craniopharyngeal canal.

CONCLUSION

Transsphenoidal glioneuronal heterotopia should be the top differential diagnosis in MR imaging if a non-enhancing nasopharyngeal mass of an infant extends through a craniopharyngeal cleft within the intersphenoid synchondrosis.