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Developmental Diseases of the Nervous System
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
James H. Tonsgard, Nikolas Mata-Machado
Encephalocele is a herniation of intracranial contents including the brain and meninges. It is a mass protruding from the skull, most commonly in the occipital area (Figure 9.6). Frontal encephaloceles are much less common, but are more frequent in the Asian population. Basal defects involving the sphenoid or ethmoid sinuses also are seen. The amount of herniated neural tissue in the defect is variable and in part determines severity of the deficits. The cause of encephaloceles is unclear although they are clearly defects in closure of the anterior neural tube. Nasofrontal lesions are thought to be due to defective separation of the neural and surface ectoderm at the site of closure of the anterior neuropore. Occipital encephaloceles may be due to defective segmentation of the bones of the posterior cranium.
Abnormal Skull Shape
Published in Amar Bhide, Asma Khalil, Aris T Papageorghiou, Susana Pereira, Shanthi Sairam, Basky Thilaganathan, Problem-Based Obstetric Ultrasound, 2019
Amar Bhide, Asma Khalil, Aris T Papageorghiou, Susana Pereira, Shanthi Sairam, Basky Thilaganathan
Encephalocele is associated with a defect of the skull. Posterior encephaloceles are much more common than at other sites. The size is variable, ranging from larger than the skull to very small—so as to easily be missed. One should also look for features of Meckel–Gruber syndrome (occipital encephalocele, polycystic kidneys, polydactyly), as it has autosomal recessive inheritance.
Congenital Tumors
Published in Asim Kurjak, CRC Handbook of Ultrasound in Obstetrics and Gynecology, 2019
Other pathological structures that should be differentiated from cystic hygroma are cervical meningomyelocele, encephalocele, and cystic teratoma of the neck. It is particularly important to distinguish encephalomeningocele and cystic hygroma on the basis of morphological criteria alone. These criteria have been described by Pearce et al.33 and serve as a useful guide for differential diagnosis. Cystic hygroma is usually characterized by the presence of typical multiple septa, contains only fluid, and is located in the posterolateral aspect of the neck. They may sometimes extend over the trunk, back, or extremities. In more than half of our cases, the cystic hygromas were larger than the fetal head. On the contrary, encephalocele is characterized by the presence of the large cyst posteriorly to the head. Although bony defect of the skull may not be seen in some cases, helpful signs which enable correct diagnosis are herniation of the brain tissue in the sac, smaller size of biparietal diameter (BPD), and presence of slight ventriculomegaly.
Association of Fetal MTHFR C677T Polymorphism with Susceptibility to Neural Tube Defects: A Systematic Review and Update Meta-Analysis
Published in Fetal and Pediatric Pathology, 2022
Razieh Sadat Tabatabaei, Neda Fatahi-Meibodi, Bahare Meibodi, Atiyeh Javaheri, Hajar Abbasi, Amaneh Hadadan, Reza Bahrami, Seyed Reza Mirjalili, Mojgan Karimi-Zarchi, Hossein Neamatzadeh
Neural tube defects (NTDs) are serious birth defects of the central nervous system (CNS) that originate during embryogenesis when the neural tube fails to close completely [1,2]. According to the reports, as morbidity and mortality from infectious diseases are decreasing globally, the contribution of birth defects to under-5 morbidity and mortality will continue to increase equally [3]. In low income countries, NTDs may account for 29% of neonatal deaths due to observable birth defects [4]. In 2016, Zaganjor et al., in a systematic review demonstrated a great variability in reported NTD prevalence estimates globally (range: 0.3–199.4 per 10,000 births) [3]. It is estimated that 1 in 1000 infants are born with a NTD annually in American Caucasians, and more are spontaneously aborted or electively terminated [5]. Open spina bifida (myelomeningocele) is the most common type of NTD and results from a failure of the closure of the neural tube along the body axis during fetal development [6,7]. Encephalocele is a type of NTD which is characterized by a meningeal sac which contains brain tissue, protruding from the skull [8,9].
Acute cerebral venous outflow obstruction during convexity meningioma resection
Published in International Journal of Neuroscience, 2021
Bo Shen, Changchen Hu, Liming Jia, Yanjun Hu
Cerebral venous outflow obstruction often refers to idiopathic intracranial hypertension (IIH), and the most common clinical condition related to IIH is dural venous sinus obstruction (stenosis). In these cases, the pathological process is often chronic with mild symptoms and rarely requires urgent surgical intervention [1]. However, acute cases of cerebral venous outflow obstruction during surgery develop an intractable intraoperative encephalocele. In clinical practice, the “intraoperative encephalocele (or intraoperative brain bulging)” is considered to be cerebral herniation. According to the classic definition, encephaloceles consist of brain tissue and meninges that have herniated through a skull defect, and although the pathology of an encephalocele involves abnormally displaced normal brain tissue, it is somewhat different from cerebral herniation. Cerebral herniation specifically refers to the displacement of brain tissue in a closed cranium, such as a subfalcine herniation, transtentorial herniation, or cerebellar tonsil herniation. However, an encephalocele is the displacement of brain tissue to the extracranial space through a skull defect [2].
Delayed presentation of morning glory disc anomaly and transsphenoidal encephalocele: A management dilemma
Published in Neuro-Ophthalmology, 2019
Jagger C. Koerner, Jared Sweeney, Charles Rheeman, Tyler J. Kenning
Cases with delayed presentation of basal encephalocele are rare but have been well documented. 4,6,9–12 Presentation in adulthood is often delayed until CSF rhinorrhea, visual field deficit, an epipharyngeal mass, or hormonal abnormality is identified. These findings can be subtle and remain subclinical for long periods of time. 4,6 In our described case, the abnormality was not detected until the patient had reached 57 years of age. This created a therapeutic dilemma, as this functionally monocular patient presented with subjective visual deterioration and automated visual fields demonstrating a bitemporal hemianopsia. Unfortunately, despite her long-standing visual difficulties, no prior examination or ophthalmologic data was available to determine if this represented a true progression of her visual defects. Progressive herniation and compression of the optic chiasm was considered as basal encephaloceles have been reported to displace the third ventricle, elements of the hypothalamic pituitary axis, anterior cerebral arteries, and optic chiasm. 6 Long-term ophthalmological follow-up with repeated visual field testing was recommended to the patient in addition to neurosurgical follow-up. She declined initial nonsurgical management, however, due to her worsening symptoms and the bitemporal defect on her automated visual fields, referring her ophthalmologic disorder to the sellar/parasellar region, as demonstrated by the MRI.