Enlarged parietal foramina: association with cerebral venous and cortical anomalies

Bilateral Foramina Parietalia Permagna - A Calvarial Defect Caused by Haploinsufficiency of the Msh Homeobox 2 Gene: A Case Report and Current Literature Review

Foramina parietalia permagna (FPP) is a rare anatomical defect that affects the parietal bones of the human skull. FPP is characterized by symmetric perforations on either side of the skull, which are caused by insufficient ossification during embryogenesis. These openings are typically abnormally large and can range from a few millimeters to several centimeters in diameter. Enlarged foramina are often discovered incidentally during anatomical or radiological examinations and in most cases left untreated unless symptoms develop. Although this calvarial defect is usually asymptomatic, it may be accompanied by neurological or vascular conditions that can have clinical significance in certain cases. FPP is an inherited disorder and arises due to mutations in either Msh homeobox 2 (MSX2) or aristaless-like homeobox 4 (ALX4) genes. In almost all cases, one parent is affected. Clinical findings and diagnostic imaging typically contribute to determine the diagnosis.

Computed-tomography evaluation of parietal foramen topography in adults: a retrospective analysis

BACKGROUND

The parietal foramen (PF) of the skull is a variable anatomic feature with important implications for venous drainage, infection, and injury. Its topography is clinically relevant for neurosurgeons for intracranial navigation and preoperative planning.

METHODS

PF topography was investigated in a series of 440 head computed-tomography scans of Omani subjects at Sultan Qaboos University Hospital. The mean age of the patients was 52 ± 17 years and there were 160 males and 280 females. The topography features of the PF, including frequency, diameter, patency, and relative position in relation to the superior sagittal sinus (SSS), were recorded. Additionally, sex and laterality differences in PF parameters were analyzed using a Chi-square test.

RESULTS

The overall prevalence of PF was 72.3% (318/440). The bilateral presence of PF was identified in 34% of skulls. Unilateral right-side prevalence was 18.2%, while left prevalence was 13.2% (p = 0.62). The prevalence of unilateral accessory PF on the right side was 1.8%, while it was 1.1% on the left (p = 0.69). PF within the sagittal suture/or intra-sutural PF was observed in 6.8% of skulls, with a frequency of 9.4% in men and 5.4% in women (p = 0.29). The diameter of the PF was 1.45 ± 0.74 mm on the right side, and 1.54 ± 0.99 mm on the left side (p = 0.96). There were 2% of incomplete PF. The PF was located over the SSS in 70.3% on the right side and 53.8% on the left side. No significant differences were observed between the PF topography parameters and sex or laterality.

CONCLUSION

The present study for the first time reports the baseline data of PF topography in a large sample of CT scans in the Arab population. The geography and race influence the PF topography differences. PF may be used as a reliable landmark of SSS. The morphological characteristics and distribution of PF reported in this study have clinical implications for imaging diagnosis, intracranial navigation of vascular disorders, and treatment.

Repair of Congenital Enlarged Parietal Foramina With Porous Polyethylene Implants

Enlarged biparietal foramina is an autosomal dominant disorder that is caused by a failure of completion of ossification within the parietal bones. Enlarged parietal foramina measuring more than a few millimeters are uncommon. Even though spontaneous regression has been described, closure is rarely complete, and depending on the size of the resulting defect, an unprotected brain is a concern. There are few reports on the surgical management of persistent enlarged biparietal foramina. This is the first report describing our experience with a custom porous polyethylene implant.

Imaging of skull vault tumors in adults

The skull vault, formed by the flat bones of the skull, has a limited spectrum of disease that lies between the fields of neuro- and musculoskeletal radiology. Its unique abnormalities, as well as other ubiquitous ones, present particular features in this location. Moreover, some benign entities in this region may mimic malignancy if analyzed using classical bone-tumor criteria, and proper patient management requires being familiar with these presentations. This article is structured as a practical review offering a systematic diagnostic approach to focal calvarial lesions, broadly organized into four categories: (1) pseudolesions: arachnoid granulations, meningo-/encephaloceles, vascular canals, frontal hyperostosis, parietal thinning, parietal foramina, and sinus pericrani; (2) lytic: fibrous dysplasia, epidermal inclusion and dermoid cysts, eosinophilic granuloma, hemangioma, aneurysmal bone cyst, giant cell tumor, metastasis, and myeloma; (3) sclerotic: osteomas, osteosarcoma, and metastasis; (4) transdiploic: meningioma, hemangiopericytoma, lymphoma, and metastasis, along with other less common entities. Tips on the potential usefulness of functional imaging techniques such as MR dynamic susceptibility (T2*) perfusion, MR spectroscopy, diffusion-weighted imaging, and PET imaging are provided.

Persistent falcine sinus with temporo-occipital schizencephaly: case report with a review of literature in relation to the undeveloped vein of Galen and/or straight sinus

Falcine sinus is a normal midline embryonic venous sinus present in the fetal brain and usually disappears by birth. Persistent falcine sinus (PFS) has been reported as a normal variant or along with vein of Galen (VOG) malformation, encephalocele, and other abnormalities. Schizencephaly, either closed or open type, has been reported with other associated vascular anomalies. We report a 22-month-old child, who presented with delayed milestones and referred for magnetic resonance (MR) imaging, and the child was found to have PFS with associated bilateral temporo-occipital closed-lip schizencephaly, hippocampal abnormalities, falco-tentorial dehiscence, and white matter abnormalities. The vein of Galen and straight sinus were absent, and the internal cerebral veins were seen draining into superior sagittal sinus via the falcine sinus. These set of abnormalities are unique from abnormalities reported previously in association with the falcine sinus.

A review of extraaxial developmental venous anomalies of the brain involving dural venous flow or sinuses: persistent embryonic sinuses, sinus pericranii, venous varices or aneurysmal malformations, and enlarged emissary veins

This paper is a narrative review of extraaxial developmental venous anomalies (eDVAs) of the brain involving dural venous flow or sinuses: persistent embryonic sinuses, sinus pericranii, enlarged emissary veins, and venous varices or aneurysmal malformations. The article highlights the natural history, anatomy, embryology, imaging, clinical implications, and neurosurgical significance of these lesions, which the authors believe represent a continuum, with different entities characterized by distinct embryopathologic features. The indications and surgical management options are discussed for these individual intracranial pathologies with relevant illustrations, and a novel classification is proposed for persistent falcine sinus (PFS). The role of neurointervention and/or microsurgery in specific cases such as sinus pericranii and enlarged emissary veins of the skull is highlighted. A better understanding of the pathophysiology and developmental anatomy of these lesions can reduce treatment morbidity and mortality. Some patients, including those with vein of Galen malformations (VOGMs), can present with the added systemic morbidity of a high-output cardiac failure. Although VOGM is the most studied and classified of the above-mentioned eDVAs, the authors believe that grouping the former with the other venous anomalies/abnormalities listed above would enable the clinician to convey the exact morphophysiological configuration of these lesions, predict their natural history with respect to evolving venous hypertension or stroke, and extrapolate invaluable insights from VOGM treatment to the treatment of other eDVAs. In recent years, many of these symptomatic venous malformations have been treated with endovascular interventions, although these techniques are still being refined. The authors highlight the broad concept of eDVAs and hope that this work will serve as a basis for future studies investigating the role of evolving focal venous hypertension/global intracranial hypertension and possibilities of fetal surgical intervention in these cases.

Identification of a novel homozygous ALX4 mutation in two unrelated patients with frontonasal dysplasia type-2

We report two unrelated boys with frontonasal dysplasias type-2 (FND-2) who shared an identical novel homozygous ALX4 mutation c.291delG (p.Q98Sfs*83). Both patients presented with a large skull defect but one had bilateral parietal meningocele-like cysts that lie along with the bony defect and increased in size with age. Scalp alopecia, hypertelorism, and clefted alae nasi were also detected in both of them. Furthermore, impalpable gonads were noted, being unilateral in one and bilateral in the other. Neuroimaging showed small dysplastic occipital lobes with dysgyria and midline subarachnoid cyst. Additional dysplastic corpus callosum and small cerebellar vermis were observed in one patient. Parietal foramina were noted in the parents of one patient. Our findings highlight the dosage effect of ALX4 and underscore the challenges of prenatal genetic counseling. Further, the indirect role of ALX4 in the development of the occipital lobe and posterior fossa is discussed.

Falcine Sinus: Incidence and Imaging Characteristics of Three-Dimensional Contrast-Enhanced Thin-Section Magnetic Resonance Imaging

Objective

To evaluate the incidence, characteristics, and variations of the falcine sinus with contrast-enhanced three-dimentional (3D) thin-section magnetic resonance (MR) images.

Materials and Methods

A retrospective review identified 1531 patients (745 males and 786 females, 2 months to 85 years) who underwent cranial MR imaging including T1-weighted imaging, T2-weighted imaging, T2-weighted fluid-attenuated inversion recovery, contrast-enhanced 3D thin-section sagittal scans, and MR venography, from June 2014 to January 2016. The incidence, characteristics of the falcine sinus, and coexisted intracranial lesions were confirmed by two neuroradiologists.

Results

Falcine sinuses were identified in 81 (38 males and 43 females) cases (5.3%, 81/1531, 5 months to 76 years of age) with calibers ranging from 2.3 mm to 17.0 mm. Three major forms of falcine sinuses were defined: arch-like (n = 47), stick-like (n = 22), and bifurcated (n = 12). Persistent falcine sinuses were found in 57 cases, among which 3 cases showed complicated cerebral anomalies, and 2 cases showed smaller straight sinuses. Recanalization of falcine sinuses were found in 24 cases, including 17 cases with tumor compression, 6 cases with cerebral venous sinus thrombosis, and one case with hypertrophic meningitis.

Conclusion

Falcine sinus is not as rare as has been reported previously. Most falcine sinuses are not associated with congenital cerebral abnormalities. Diseases that cause increased pressure in the venous sinus may lead to recanalization of falcine sinus. Illustrating the characteristics of falcine sinus may prompt a more comprehensive understanding and diagnosis of associated diseases, and avoid potential surgical damage in the future.

Asymmetrically enlarged parietal foramina in a rare case of Goldenhar syndrome with a possible etiopathogenesis

Goldenhar´s syndrome (GS) also known as oculo-auriculo-vertebral spectrum (OAVS) is a relatively rare condition. GS is of multifactorial etiology that includes environmental and/or genetic factors, in addition to teratogens that disturb the blastogenesis. A 5-year-old girl from Saudi Arabia, was a member of dizygotic twins conceived by assisted reproductive technology (ART), and born with features of GS. She had asymmetrical face, cleft lip and palate, right microphthalmia and microtia. Radiological imaging showed right maxillary and mandibular bone hypoplasia, asymmetrically enlarged parietal foramina, a persistent midline occipital foramen, abnormal bone arising from occipital bone, extending along tentorium cerebelli, and a lipoma at the right tentorium cerebelli. A rudimentary right eye with dermoid cyst and pseudotumor as well as bilateral atresia of external auditory canals were present. Karyotyping was normal. ART and the risk of manipulation of ovum/embryo, was shown to be associated with multiple gestation and an increased risk of major birth defects. Given that our patient was from Eastern-province close to the South of Iraq, where Gulf wars took place and the reported incidence of birth defects, including orofacial malformation, jumped there to about seven-folds, after war, thus, environmental contamination, and the possible teratogenic effect of depleted uranium could not be excluded. In conclusion, our case of GS, disclosed a rare radiological finding in calvarial anatomy, and asserted that, careful clinical evaluation is recommended in cases of GS. ART fertilization risk along with the possible parental environmental exposure were regarded as the potential cooperators of multifactorial etiology in our case.

Cranium Bifidum Occultum Associated with Hypertelorism Treated with Posterior Vault Reconstruction and Orbital Box Osteotomies: Case Report and Technical Note

Cranium bifidum occultum is a disorder of skull ossification presenting as an enlarged posterior fontanelle in the upper posterior angle of the parietal bone near the intersection of the sagittal and lambdoid sutures. The standard treatment for cranium bifidum occultum is observation. We present a case of a 5-year-old boy who presented with a 15 × 4.5 cm midline posterior cranial vault defect consistent with diagnosis of cranium bifidum occultum associated with orbital hypertelorism and a widened nose. The patient underwent posterior vault reconstruction for correction of cranium bifidum occultum defect followed by bifrontal craniotomy and orbital box osteotomies for correction of orbital hypertelorism and nasal deformity. To our knowledge, this is the first reported case describing surgical treatment for cranium bifidum occultum associated with orbital hypertelorism.

Foramina parietalia permagna: familial and radiological evaluation of two cases and review of literature

PURPOSE

Foramina parietalia permagna is a variable intramembranous ossification defect of the parietal bones. Foramina parietalia permagna have an autosomal dominant inheritance, and it is showed that mutations in chromosome 5 and 11 are causing this anomaly. Enlarged parietal foramina occurs extremely rare. They are usually asymptomatic, but occasional headache, vomiting, pain over unprotected cerebral cortex, and seizures may be experienced by the patients. In the literature, some associated congenital bony defects, soft tissue pathologies, underlying neuronal deficits, and vascular variations have been described.

METHODS

We report two cases of foramina parietal permagna with their pedigrees and genetic analysis.

RESULTS

In case 1, cytogenetic analysis revealed a mutation of the ALX4 gene and all of the members of the family diagnosed with FPP. MRI revealed inferior vermian cerebellar hypoplasia. Surgery was not considered. In case 2, cytogenetic analysis could not be obtained because of financial reasons. Cranial MRI revealed hypoplastic right transverse sinus and sigmoid sinus, with a persistent parafalcine sinus. Surgery was not considered.

CONCLUSION

Despite of its rarity, genetic background and some important associated anomalies make foramina parietalia permagna more than an uncommon insignificant genetic disorder.

An Osteologic Study of Cranial Opening of Optic Canal in Gujarat Region

INTRODUCTION

Optic canal is a bony canal situated in between the roots of lesser wings of sphenoid, lateral to body of sphenoid. It transmits optic nerve and ophthalmic artery, surrounded by meninges. Various authors have studied variations in skull foramina and correlated clinically, as variants in the body structures have been found to be associated with many inherited or acquired diseases.

AIM

The present study aimed to examine morphologic and morphometric variations in cranial openings of optic canals.

MATERIALS AND METHODS

The study was undertaken in total 150 dry adult human skulls. The variations in size, shape, presence or absence and duplication or multiplication if any, in optic canal were observed bilaterally. Unusual features such as recess, fissure and notch were also observed bilaterally. Student's t-test was applied to compare size of cranial openings of optic canal on both sides. Similarly, morphologic features related with the canal were studied by calculating frequency and proportions of various parameters.

RESULTS

Optic canal was present in all 150 skulls studied bilaterally. The mean maximum dimension of the canal at cranial opening was 5.03±0.72 mm on right side and 5.02±0.76 mm on left side. The shape of the canal was ovoid at cranial opening in all the skulls studied. Duplication of optic canal was present in one skull on left side. Recess was found in 105(35%) sides of total skulls observed. Fissure was found in 20(6.67%) sides and notch was observed in 30(10%) sides of total skulls.

CONCLUSION

The optic canal showed variability in various parameters. Knowledge regarding variations in size, shape and unusual features on cranial opening of optic canal can be helpful to clinicians while approaching optic canal for various invasive procedures such as optic nerve decompression.

Neuroimaging Findings in Pediatric Genetic Skeletal Disorders: A Review

Genetic skeletal disorders (GSDs) are a heterogeneous group characterized by an intrinsic abnormality in growth and (re-)modeling of cartilage and bone. A large subgroup of GSDs has additional involvement of other structures/organs beside the skeleton, such as the central nervous system (CNS). CNS abnormalities have an important role in long-term prognosis of children with GSDs and should consequently not be missed. Sensitive and specific identification of CNS lesions while evaluating a child with a GSD requires a detailed knowledge of the possible associated CNS abnormalities. Here, we provide a pattern-recognition approach for neuroimaging findings in GSDs guided by the obvious skeletal manifestations of GSD. In particular, we summarize which CNS findings should be ruled out with each GSD. The diseases (n = 180) are classified based on the skeletal involvement (1. abnormal metaphysis or epiphysis, 2. abnormal size/number of bones, 3. abnormal shape of bones and joints, and 4. abnormal dynamic or structural changes). For each disease, skeletal involvement was defined in accordance with Online Mendelian Inheritance in Man. Morphological CNS involvement has been described based on extensive literature search. Selected examples will be shown based on prevalence of the diseases and significance of the CNS involvement. CNS involvement is common in GSDs. A wide spectrum of morphological abnormalities is associated with GSDs. Early diagnosis of CNS involvement is important in the management of children with GSDs. This pattern-recognition approach aims to assist and guide physicians in the diagnostic work-up of CNS involvement in children with GSDs and their management.

Atretic cephaloceles: a comprehensive analysis of historical cohort

PURPOSE

This study aims to analyze the historical cohort of patients with atretic cephaloceles (ACs) comprehensively, since the literature regarding ACs is limited by small case series or case reports and to report a new venous anomaly concomitant with a parietal AC in our exemplary case.

METHODS

After a PubMed/Medline search with "atretic cephalocele" in April 2016, we retrieved 42 articles, 41 of which were relevant with the topic. Full texts of accessible articles and abstracts of inaccessible articles were read comprehensively. References of retrieved articles were manually searched. Additional 29 articles reporting the cases of atretic, rudimentary, occult, or sequestered cephaloceles were accessed, since these terms have been used interchangeably in the literature.

RESULTS

Median age and mean age of the patients were 1 and 6.69 years, respectively. Female/male ratio was 1.03:1. Atretic cephaloceles were located in different regions, in decreasing order of frequency: parietal (55 %; n = 105), occipital (37 %; n = 71), parieto-occipital (n = 8), frontal (n = 4), asterion (n = 1), and sincipital (n = 1). Concomitant central nervous system (CNS) anomalies were present in 73.3 % of patients with parietal atretic cephaloceles and in 32.4 % of patients with occipital atretic cephaloceles (p < 0.0001). We realized that all patients with worse outcomes had concomitant CNS anomalies (100 %), whereas only 48 % of those with good clinical outcomes had concomitant anomalies (p = 0.0248).

CONCLUSIONS

Atretic cephaloceles present as nodular extrusions on the parietal and occipital regions. Concomitant CNS anomalies, which impair the clinical outcomes, are more common in patients with parietal ACs. Observation-only approach is enough in patients with asymptomatic ACs. However, life-long follow-ups are required, because of recurrence after the surgery.

The extracranial to intracranial anastomotic channel through the parietal foramen: delineation with magnetic resonance imaging

PURPOSE

Parietal foramina (PFs) are openings of fine canals that perforate the parietal bone. However, few studies have investigated the entire canals and their emissary vessels (EVs). Here, we explore the EVs with magnetic resonance imaging.

METHODS

A total of 104 patients who underwent contrast examinations and exhibited an intact scalp, skull, dura mater, and superior sagittal sinus were enrolled in this study. Imaging data were obtained as thin-sliced, seamless sagittal sections and were transferred to a workstation for analysis.

RESULTS

A total of 116 EVs passing through the PF and inner canals (parietal canal) were identified in 78 patients (75 %). All the EVs were found to perforate each layer of the parietal bone. Of 104 patients, 68 % exhibited one EV, 30 % two EVs, and 2 % three EVs. In 85.3 %, the EV was entirely delineated in one sagittal slice, 10.3 % were covered by two slices, and 4.3 % by three slices. In 68 %, the EV connected to the upper surface of the superior sagittal sinus (SSS) with variable courses from near-vertical to horizontal inclinations.

CONCLUSIONS

EVs perforate the skull with variable inclinations, while showing a highly consistent course in the sagittal dimension. The PF and EV can be used as landmarks of the SSS lying immediately below.

Enlarged parietal foramina: a rare forensic autopsy finding

Enlarged parietal foramina (EPF) are a quite rare developmental defect of the parietal bone which has to be distinguished from the normal small parietal foramina. We report a forensic case of an individual found in an advanced state of putrefaction in his own house with an undetermined cause of death. No evidence of trauma was observed, and the toxicological exam was negative. The victim was a 40-year-old man with a history of epilepsy. The large biparietal foramina, a rare anatomical variation and unusual autopsy finding, were observed at autopsy. The recognition of anatomical variations is important to avoid false interpretations and conclusions and has a significant potential as an identity factor, thus contributing to positive identification.

Polymicrogyria: pathology, fetal origins and mechanisms

Polymicrogyria (PMG) is a complex cortical malformation which has so far defied any mechanistic or genetic explanation. Adopting a broad definition of an abnormally folded or festooned cerebral cortical neuronal ribbon, this review addresses the literature on PMG and the mechanisms of its development, as derived from the neuropathological study of many cases of human PMG, a large proportion in fetal life. This reveals the several processes which appear to be involved in the early stages of formation of polymicrogyric cortex. The most consistent feature of developing PMG is disruption of the brain surface with pial defects, over-migration of cells, thickening and reduplication of the pial collagen layers and increased leptomeningeal vascularity. Evidence from animal models is consistent with our observations and supports the notion that disturbance in the formation of the leptomeninges or loss of their normal signalling functions are potent contributors to cortical malformation. Other mechanisms which may lead to PMG include premature folding of the neuronal band, abnormal fusion of adjacent gyri and laminar necrosis of the developing cortex. The observation of PMG in association with other and better understood forms of brain malformation, such as cobblestone cortex, suggests mechanistic pathways for some forms of PMG. The role of altered physical properties of the thickened leptomeninges in exerting mechanical constraints on the developing cortex is also considered.

MRI findings of intracranial anomalies associated with cephalocele--a case series

INTRODUCTION

Cephalocele is a relatively rare cranial dysraphism characterised by herniation of intracranial structures through the skull. Surgical management is primarily necessary where a risk of infection through communication of the lesion with the intracranial space exists, a risk of rupture, or for cosmetic purposes. Cephalocele is often associated with venous anomalies such as vertical embryonic positioning of the straight sinus, splitting of the superior sagittal sinus, vein of Galen elongation, along with tenting of the tentorium [Morioka et al. Childs Nerv Syst 25:309-315, 2009]

PATIENTS

Here, we report four cases of cephalocele with pre-operative MRI imaging retrospectively studied, demonstrating associated venous anomalies. Three of these patients went on to have uncomplicated, corrective surgery, while one was managed conservatively.

RESULTS

All four cases demonstrated the main venous drainage going through a persistent falcine sinus to drain into the superior sagittal sinus. Upward tenting of the tentorium was observed in three cases (cases 1, 3 and 4). Two of our cases demonstrated other venous anomalies frequently reported in the literature, namely splitting of the superior sagittal sinus and absence of the transverse sinus (case 1) and communication of the cephalocele with the superior sagittal sinus and absence of the straight sinus (case 2).

CONCLUSION

The association between cephalocele and venous anomalies suggests that pre-operative MRI should be mandatory for a full evaluation of a suspicious midline cranial lesion in order to evaluate the safety of corrective surgery.

Triple falx cerebelli associated with two aberrant venous sinuses in the floor of posterior cranial fossa

During regular dissection classes, we came across tripled falx cerebelli in a male cadaver. The main (middle) falx cerebelli was large and was attached to the internal occipital crest. It contained the occipital sinus. There were two smaller folds (right and left), one on either side of the falx cerebelli. There were two aberrant venous sinuses; each one connecting the ipsilateral sigmoid and transverse sinuses with each other. The complex dural-venous variation reported here is seldom reported in the literature. Knowledge of such variation is important for neurosurgeons and neuroradiologists as these aberrant folds could cause haemorrhage during suboccipital approaches or may lead to erroneous interpretation during imaging of the posterior cranial fossa.

Large parietal midline defect with unusual ridge-like structure at the rim and persistent falcine sinus

BACKGROUND

Midline cranial defects can be divided into lesions with intracranial tissue herniation (cranium bifidum cysticum) and lesions mainly with ossification failure (cranium bifidum occultum). Herniated cephaloceles mostly require surgical resection, while persisted parietal foramina might become smaller with age.

CLINICAL CASE

Here, we report a neonate with large symmetric midline skull defect at high parietal area. A mild bulging mass was noticed. Interestingly, unlike sac herniation, it was surrounded by bony ridges extended from the rim of the calvarial defect, which suggests aberrant ossification. Persistent falcine sinus was also detected. At the corrected age of 11 months, the size of the skull defect had decreased spontaneously, favoring the diagnosis of parietal bone ossification defect. Potential mechanisms resulting in the special appearance of skull bone were discussed.

CONCLUSION

Incomplete closing of the parietal foramina might be expected due to the aberrant ridge formation. We suggest protective measures for the calvarial defect.

Enlarged parietal foramina: a rare finding in a female Greek skull with unusual multiple Wormian bones and a rich parietal vascular network

Enlarged parietal foramina (>5 mm) is an extremely rare developmental defect of the parietal bone, which is distinguished from the normal small parietal foramina, as genes associated with this entity have been identified, suggesting that it is hereditary in nature. We describe a dry skull of a 35-year-old female, with enlarged parietal foramina symmetrically situated bilaterally, oval in shape, measuring 4.5 × 9.3 mm (right) and 4.9 × 9.2 mm (left) in size. The foramina coexisted with multiple Wormian bones in several sites of the skull. On the inner parietal bone surface, the anterior, posterior and lateral foramina's rims carried grooves, which were continuous with the middle meningeal vessels' branches, indicating that a rich vascular network existed around the foramina. These vascular grooves also notched the external table at the margin of the foramina, which suggests a potential communication between the meningeal and the scalp vessels. In addition, this vascular variation should be taken into consideration when performing surgical interventions in the area, because the large vascular supply to the foramina is a possible source of extensive bleeding. Moreover, the interaction of intracranial and extracranial veins and the fact that the blood flows in them in both directions, as they are valveless, could represent a possible pathway for infections to spread in the cranial cavity.

Enlarged parietal foramina: a review of genetics, prognosis, radiology, and treatment

INTRODUCTION

Enlarged parietal foramina are variable ossification defects in the parietal bones that present as symmetric radiolucencies on skull radiographs. In contrast to the normal small parietal foramina, enlarged parietal foramina are a hereditary condition and genes associated with it have been identified.

METHODS

A literature review was performed to discuss the many known findings related to enlarged parietal foramina.

CONCLUSIONS

Even though they remain asymptomatic in the majority of cases, they may be associated with other pathologies and occasionally become symptomatic. This article provides a comprehensive review of the current knowledge of enlarged parietal foramina.

An enlarged parietal foramen in the late archaic Xujiayao 11 neurocranium from Northern China, and rare anomalies among Pleistocene Homo

We report here a neurocranial abnormality previously undescribed in Pleistocene human fossils, an enlarged parietal foramen (EPF) in the early Late Pleistocene Xujiayao 11 parietal bones from the Xujiayao (Houjiayao) site, northern China. Xujiayao 11 is a pair of partial posteromedial parietal bones from an adult. It exhibits thick cranial vault bones, arachnoid granulations, a deviated posterior sagittal suture, and a unilateral (right) parietal lacuna with a posteriorly-directed and enlarged endocranial vascular sulcus. Differential diagnosis indicates that the perforation is a congenital defect, an enlarged parietal foramen, commonly associated with cerebral venous and cranial vault anomalies. It was not lethal given the individual’s age-at-death, but it may have been associated with secondary neurological deficiencies. The fossil constitutes the oldest evidence in human evolution of this very rare condition (a single enlarged parietal foramen). In combination with developmental and degenerative abnormalities in other Pleistocene human remains, it suggests demographic and survival patterns among Pleistocene Homo that led to an elevated frequency of conditions unknown or rare among recent humans.

Confirmation of the Zechi-Ceide syndrome

Atretic cephaloceles associated with multiple congenital anomalies are known to follow either autosomal dominant or autosomal recessive patterns of inheritance. Zechi-Ceide syndrome (OMIM 612916) is an autosomal recessive disorder, characterized by an occipital atretic cephalocele, characteristic facial features, and large feet. Here we describe a patient with findings fitting Zechi-Ceide syndrome, in whom some of the manifestations were also present in his mother, indicating either autosomal dominant inheritance with variable expression, X-linked inheritance, or a manifesting carrier of an autosomal recessive inheritance.

Giant encephalocele: a study of 14 patients

BACKGROUND

Giant encephalocele is a rare condition and few published reports are available in the English literature. It is a challenge to neurosurgeons, even today. This series consists of 14 patients with giant encephaloceles treated at our institute.

MATERIAL AND OBSERVATION

Over a period of 8 years, from 2002 to 2009, 110 patients with encephaloceles were managed at our institute. Amongst them, 14 were children with giant encephaloceles. All patients had CT/MRI or both prior to surgery, and all were operated upon. Four patients were neonates, under 1 month of age, and 9/14 patients (64%) were under 3 months. The youngest child was a newborn baby aged 2 days. Except for 1 with an anterior encephalocele, the rest were patients with occipital encephaloceles. A CT scan was performed on 5 and an MRI on 1 patient. Both CT and MRI scans were performed on the other 8 patients. MRI/CT showed hydrocephalus in 10/14 patients. Of these, 7 required ventriculoperitoneal (VP) shunt, and the remaining 3 with mild to moderate hydrocephalus did not. Of the 7 patients who underwent VP shunt, 5 had a shunt during the encephalocele repair and 2 had a postoperative shunt for increasing hydrocephalus.

RESULTS

Other associated anomalies recorded were acquired Chiari malformation in 3 patients, secondary craniostenosis with microcephaly in 5, and syringomyelia in 1 patient. All the patients underwent repair of encephalocele and 4 had suturectomy of coronal suture for the secondary craniostenosis. There were 2 postoperative deaths due to hypothermia. Among the 12 surviving patients, 9 had a good outcome and 3 had poor mental development. The present study shows overall good outcomes in 9/14 (66%) patients.

Two cases with persistent falcine sinus as congenital variation

The falcine sinus is an abnormal anatomic structure located in the falx cerebri that is closed after birth and is rarely observed. We describe two cases of persistent falcine sinus. A 60-year-old woman presented with headache. An 11-year-old girl presented with intermittent headache and a palpable scalp mass in the middle of the high parietal area. The straight sinuses were absent in both patients. In both patients, drainage of the galenic system took place through a sinus within the falx, also known as a falcine sinus. Suspicious dysplastic tentorium cerebelli was observed in one patient. It can be concluded that a mesenchymal disorder can be the primary cause for a persistent falcine sinus.

Syndromes, disorders and maternal risk factors associated with neural tube defects (VII)

Neural tube defects (NTDs) may be associated with syndromes, disorders and maternal risk factors. This article provides a comprehensive review of the syndromes, disorders and maternal risk factors associated with NTDs, including DK phocomelia syndrome (von Voss-Cherstvoy syndrome), Siegel-Bartlet syndrome, fetal warfarin syndrome, craniotelencephalic dysplasia, Czeizel-Losonci syndrome, maternal cocaine abuse, Weissenbacher- Zweymller syndrome, parietal foramina (cranium bifidum), Apert syndrome, craniomicromelic syndrome, XXagonadism with multiple dysraphic lesions including omphalocele and NTDs, Fryns microphthalmia syndrome, Gershoni-Baruch syndrome, PHAVER syndrome, periconceptional vitamin B6 deficiency, and autosomal dominant Dandy-Walker malformation with occipital cephalocele. NTDs associated with these syndromes, disorders and maternal risk factors are a rare but important cause of NTDs. The recurrence risk and the preventive effect of maternal folic acid intake in NTDs associated with syndromes, disorders and maternal risk factors may be different from those of nonsyndromic multifactorial NTDs. Perinatal diagnosis of NTDs should alert doctors to the syndromes, disorders and maternal risk factors associated with NTDs, and prompt thorough etiologic investigation and genetic counseling.

Parietal bone defect: differential diagnosis and neurologic associations

Parietal bone defects are rare and exhibit variable etiologies. We report on a 16-year-old girl with an isolated, giant parietal bone defect with encephalomalacia, and an asymptomatic Rathke's cleft cyst. The patient presented with epilepsy. We discuss the differential diagnosis and pertinent neurologic associations. Irrespective of cause, parietal bone defects remain a benign clinical entity. However, it is important to define the extent of the bone defect and associated intracranial abnormalities, and if needed, to take early preventive steps, medical as well as surgical, against potential brain damage.

Complete cranium bifidum without scalp abnormality. Case report

Cranium bifidum is an unusual lesion in newborns. The majority of previously reported cases have described enlarged parietal foramina with some scalp and other congenital abnormalities. In this report the authors present the first case of complete cranium bifidum without any other anomaly. The cranial defect persisted for 3 years during the follow-up period. No hereditary or familial transition has been observed. The authors conclude that such an extremely rare occurrence of complete cranium bifidum may be a result of a coincidental mutation.

Linkage to chromosome 2q36.1 in autosomal dominant Dandy-Walker malformation with occipital cephalocele and evidence for genetic heterogeneity

We previously reported a Vietnamese-American family with isolated autosomal dominant occipital cephalocele. Upon further neuroimaging studies, we have recharacterized this condition as autosomal dominant Dandy-Walker with occipital cephalocele (ADDWOC). A similar ADDWOC family from Brazil was also recently described. To determine the genetic etiology of ADDWOC, we performed genome-wide linkage analysis on members of the Vietnamese-American and Brazilian pedigrees. Linkage analysis of the Vietnamese-American family identified the ADDWOC causative locus on chromosome 2q36.1 with a multipoint parametric LOD score of 3.3, while haplotype analysis refined the locus to 1.1 Mb. Sequencing of the five known genes in this locus did not identify any protein-altering mutations. However, a terminal deletion of chromosome 2 in a patient with an isolated case of Dandy-Walker malformation also encompassed the 2q36.1 chromosomal region. The Brazilian pedigree did not show linkage to this 2q36.1 region. Taken together, these results demonstrate a locus for ADDWOC on 2q36.1 and also suggest locus heterogeneity for ADDWOC.

Occipital atretic cephalocele, striking facial anomalies, and large feet in three siblings of a consanguineous union

Here, we report a newly recognized syndrome in three siblings with occipital atretic cephalocele, striking facial anomalies, and large feet. Specific findings include occipital atretic cephalocele, hypoplastic cerebellar vermis, Dandy-Walker variant, mental deficiency, prominent forehead, midface deficiency, broad nose and nasal root, grooved nasal tip, abnormal nares, narrow malformed ears, severe oligodontia, and large wide feet with a gap between the hallux and the second toe. The phenotype is variable in the three patients. The finding of three affected siblings of a consanguineous couple strongly suggests autosomal recessive inheritance.

Anatomy of the falcine venous plexus

Object

The superior and inferior sagittal sinuses have been well studied. Interestingly, other venous structures within the falx cerebri have received scant attention in the medical literature. The present study was performed to elucidate the presence and anatomy of these midline structures.

Methods

The authors examined 27 adult latex- or ink-injected cadaveric specimens to observe the morphological features of the sinuses within the falx cerebri (excluding the inferior and superior sagittal sinuses).

Results

All specimens were found to have an extensive network of small tributaries within the falx cerebri that were primarily concentrated in its posterior one third. In this posterior segment, these structures were usually more pronounced in the inferior two thirds. The portion of the falx cerebri not containing significant falcine venous sinus was termed a “safe area.” These vascular channels ranged in size from 0.5 mm to 1.1 cm (mean 0.6 mm); 100% of these vessels communicated with the inferior sagittal sinus. Classification of the structures was then performed based on communication of the falcine venous sinus with the superior sagittal sinus. Type I falcine sinuses had no communication with the superior sagittal sinus, Type II falcine sinuses had limited communication with the superior sagittal sinus, and Type III falcine sinuses had significant communication with the superior sagittal sinus. Seventeen (63%) of 27 specimens communicated with the superior sagittal sinus (Types II and III). Further subdivision revealed 10 Type I, seven Type II, and 10 Type III falcine venous plexuses.

Conclusions

There are other venous sinuses in the falx cerebri in addition to the superior and inferior sagittal sinuses. Neurosurgical procedures that necessitate incising or puncturing the falx cerebri can be done more safely via a described safe area. Given that the majority of specimens in the authors' study were found to have a plexiform venous morphology within the falx cerebri, they propose that these channels be referred to as the falcine venous plexus and not sinus. The falcine venous plexus should be taken into consideration by the neurosurgeon.

Transcranial puncture through the parietal and mastoid foramina for the treatment of dural fistulas

✓ In this report the authors describe the endovascular treatment of dural arteriovenous fistulas (DAVFs) through trans-cranial puncture of the feeding arteries. Four patients had DAVFs that were fed by occipital arteries (OAs) that supplied blood to the intracranial meningeal arteries via the transcranial branches and coursed through the parietal and mastoid foramina. Due to the excessive tortuosity of the OA, conventional endovascular navigation had failed in all cases. Transcranial puncture of the meningeal feeding arteries was performed through the parietal or mastoid foramen, allowing navigation with a microcatheter until the level of the shunts. Complete cure of the DAVF was attained in all patients after injection of acrylic glue.

Hereditary cranium bifidum persisting as enlarged parietal foramina (Catlin marks) on cephalometric radiographs

Cranium bifidum occultum is a rare skull ossification disorder referred to as the Catlin mark characterized by ossification defects in the parietal bones. Evidence suggests that this condition has a strong genetic heterogenicity. It is believed that, as calvarial growth continues, ossification in parietal bones fills these defects, and they can remain as parietal foramina on either side of the sagittal suture. During the conversion phase of cranium bifidum to the persistent parietal foramen, there will be periods when the brain is unprotected because of the delay in the ossification of the parietal bones. This report describes cranium bifidum occultum diagnosed as an incidental finding in a 14-year-old boy who initially had large bilateral unossified parietal bones and many congenital abnormalities. The patient underwent various surgical procedures over 6 years for the correction of cleft lip and palate. With craniofacial corrections and orthodontic treatment, the patient now has stable dentition and a firm palate with most of the parietal bones ossified. Cranioplasty was not recommended by his family physician after consultation with a neurosurgeon. Orthodontists should be familiar with this genetic abnormality because it causes delay in parietal bone ossification, and they should be able to distinguish between anatomic parietal foramina and enlarged parietal foramina (persistent unossified areas of cranium bifidum occultum), especially when craniofacial abnormalities are noticed.

An incidental persistent falcine sinus with dominant straight sinus and hypoplastic distal superior sagittal sinus

An incidental persistent falcine sinus was detected in an otherwise normal brain on MRI in a 12-year-old girl who underwent imaging after clinical suspicion of acute disseminated encephalomyelitis. The falcine sinus was associated with a hypoplastic posterior third of the superior sagittal sinus and a dominant straight sinus. Generally, atresia or hypoplasia of the straight sinus is associated with a persistent falcine sinus in postnatal life; otherwise, the falcine sinus disappears before birth. We discuss the embryological basis for such an association in this case.

Surgical management of foramina parietalia permagna

Enlarged parietal foramina are rare congenital skull defects identified on physical examination and confirmed radiographically. They are round or oval defects situated on each parietal bone approximately 1 cm from the midline and 2 to 3 cm superior to the lambdoid suture. Although small parietal foramina are common variants in up to 60% to 70% of normal skulls, large parietal foramina ranging from 5 mm to multiple centimeters are less common, with a prevalence of 1:15,000 to 1:25,000. We present a case series of four patients with large persistent parietal foramina managed surgically for the correction of this deformity. Two infants were treated with autologous calvarial bone grafts, and two were treated with a mesh plating system and hydroxyapatite. No patient developed any perioperative complications. No perioperative or delayed infections occurred in our patient population. The mean postoperative follow-up was 36 months. One patient required a second procedure with methylmethacrylate because of late bone graft failure, whereas the others were successfully treated by the initial procedure. Foramina parietalia permagna, otherwise known as fenestrae parietals symmetricae, enlarged parietal foramina, giant parietal foramina, or Catlin marks, are a rare clinical entity. A spontaneous decrease in the size of these defects with growth of the infant has been reported, but this closure is usually incomplete. Surgical intervention of persistent large foramina protects the child against potential injury to the underlying brain. We advocate cranioplasty for active young children and those at risk for injury (i.e., seizure disorder) to decrease the risk for potential intracranial injury.

The ALX4 homeobox gene is mutated in patients with ossification defects of the skull (foramina parietalia permagna, OMIM 168500)

Foramina parietalia permagna (FPP) (OMIM 168500) is caused by ossification defects in the parietal bones. Recently, it was shown that loss of function mutations in the MSX2 homeobox gene on chromosome 5 are responsible for the presence of these lesions in some FPP patients. However, the absence of MSX2 mutations in some of the FPP patients analysed and the presence of FPP associated with chromosome 11p deletions in DEFECT 11 (OMIM 601224) patients or associated with Saethre-Chotzen syndrome suggests genetic heterogeneity for this disorder. Starting from a BAC/P1/cosmid contig of the DEFECT 11 region on chromosome 11, we have now isolated the ALX4 gene, a previously unidentified member of the ALX homeobox gene family in humans. Mutation analysis of the ALX4 gene in three unrelated FPP families without the MSX2 mutation identified mutations in two families, indicating that mutations in ALX4 could be responsible for these skull defects and suggesting further genetic heterogeneity of FPP.