Unruptured giant lateral thoracic meningocele: extremely rare cause of cerebrospinal fluid (CSF) hypotension in neurofibromatosis type 1.

Neurofibromatosis type 1 (NF1) is a multisystem neurocutaneous disorder. Scoliosis and dural ectasia are features of the associated mesodermal dysplasia. Lateral thoracic meningoceles can develop in NF1 and progressively enlarge due to cerebrospinal fluid (CSF) pulsations. Large meningoceles can cause compressive symptoms in the thorax. We are reporting a case of a NF1 presenting with acute onset respiratory distress, who also had chronic orthostatic headaches. CT chest showed unruptured enlarging bilateral lateral thoracic meningoceles causing lung compression. MRI of the brain and spine showed features of CSF hypotension, explaining the headaches. CSF hypotension with unruptured meningoceles is extremely rare. Management of the condition is challenging since surgical removal is prone to complications due to underlying mesodermal abnormalities. Cystoperitoneal shunting to relieve lung compression may worsen CSF hypotension. A shunt with a programmable valve allowed controlled drainage and successfully relieved lung compression without worsening of orthostatic headaches in our case.

Posterior median surgical approach to anterior sacral meningocele complicated by rectothecal fistula.

In this case report, we aimed to describe the clinical presentation, surgical approach, and follow-up of a patient with rare anterior meningocele associated with rectothecal fistula. An 17-year-old female patient was admitted to the emergency department with meningitis. On further examinations, an anterior sacral meningocele accompanied by rectothecal fistula was detected. Appropriate antibiotic treatment was arranged and surgical plan was made with the pediatric surgery clinic. The patient underwent meningocele repair via posterior approach and colostomy operation. The patient did not experience any neurological issues after the surgery. The colostomy was reversed 3 months later, and third-month follow-up MRI showed complete regression of the meningocele sac with no neurological complications. Anterior meningocele accompanied by a rectothecal fistula is a rare and complicated case. Only seven cases of coexisting ASM and RTF have been reported in literature. Although both anterior and posterior approaches have been used for the treatment of ASM, the choice of treatment is essentially based on the patient's clinical and imaging findings.

Association of spinal cord abnormalities with vertebral anomalies: an embryological perspective.

PURPOSE: To analyze the relationship between spinal cord and vertebral abnormalities from the point of view of embryology. METHODS: We analyzed the clinical and radiological data of 260 children with different types of spinal cord malformations in combination with vertebral abnormalities. RESULTS: Among 260 individuals, approximately 109 presented with open neural tube defects (ONTDs), 83 with split cord malformations (SCMs), and 83 with different types of spinal lipomas. Pathological spina bifida emerged as the most frequent vertebral anomaly, affecting 232 patients, with a higher prevalence in ONTD. Vertebral segmentation disorders, including unsegmented bars, butterfly vertebrae, and hemivertebrae, were present in 124 cases, with a higher prevalence in SCM. The third most common spinal anomaly group consisted of various forms of sacral agenesis (58 cases), notably associated with blunt conus medullaris, spinal lipomas, and sacral myelomeningocele. Segmental aplasia of the spinal cord had a typical association with segmental spinal absence (N = 17). CONCLUSION: The association between SCM and neuroenteric cyst/canal and vertebral segmentation disorders is strong. High ONTDs often coincide with pathological spina bifida posterior. Type 1 spinal lipomas and focal spinal nondisjunction also correlate with pathologic spina bifida. Segmental spinal absence or dysgenesis involves localized spinal and spinal cord aplasia, sometimes with secondary filar lipoma.

Long-term outcomes in sacral agenesis.

INTRODUCTION: Sacral agenesis (SA) includes a range of clinical presentations of varying severity, with implications for function and quality of life (QoL). Diagnosis is often made perinatally, and prognostic discussions become an important aspect of parental counselling. This study engaged SA sufferers and their caregivers to obtain objective, long-term patient reported outcome data. METHOD: Patients with radiologically confirmed SA from a single tertiary spinal unit underwent retrospective medical record review. Patients were then contacted by telephone to complete QoL questionnaires including EQ-ED-5L for adults and EQ-ED-Y for < 16-year-olds. Additional information including Renshaw grade, employment, living situation and bladder function was also collected. RESULTS: Twenty-six patients with SA were identified. Mean age is 23.35 years (range 0.92-63.53), 13 M:17F. Renshaw grade ranged from 1 to 4. Sixty-eight percent had associated kyphoscoliotic deformities. The majority (70%) had either impaired or absent bladder control, and 80% need walking aids to mobilise. Twenty patients completed the questionnaire (10 adults and 10 < 16-year-olds). Mean EQ-ED-5L index for adults was +0.474 (range -0.1 to +0.089, 1 = best), with a lower mean value of +0.287 (range -0.54 to +1) for the < 16-year cohort. Those undergoing spinal fusion procedures had significantly lower scores (-0.08 v +0.44, p = 0.022). CONCLUSION: This study provides an objective record of the QoL of individuals with SA, illustrating a wide variety of outcomes, with differences between younger and older individuals which may reflect the results of a long-term adaptive process. The implications for individuals should be carefully tailored to the specific deformity and the likely underlying neurological deficits.

A topographical analysis of encephalocele locations: generation of a standardised atlas and cluster analysis.

OBJECTIVE: Encephaloceles are considered to result from defects in the developing skull through which meninges, and potentially brain tissue, herniate. The pathological mechanism underlying this process is incompletely understood. We aimed to describe the location of encephaloceles through the generation of a group atlas to determine whether they occur at random sites or clusters within distinct anatomical regions. METHODS: Patients diagnosed with cranial encephaloceles or meningoceles were identified from a prospectively maintained database between 1984 and 2021. Images were transformed to atlas space using non-linear registration. The bone defect, encephalocele and herniated brain contents were manually segmented allowing for a 3-dimensional heat map of encephalocele locations to be generated. The centroids of the bone defects were clustered utilising a K-mean clustering machine learning algorithm in which the elbow method was used to identify the optimal number of clusters. RESULTS: Of the 124 patients identified, 55 had volumetric imaging in the form of MRI (48/55) or CT (7/55) that could be used for atlas generation. Median encephalocele volume was 14,704 (IQR 3655-86,746) mm3 and the median surface area of the skull defect was 679 (IQR 374-765) mm2. Brain herniation into the encephalocele was found in 45% (25/55) with a median volume of 7433 (IQR 3123-14,237) mm3. Application of the elbow method revealed 3 discrete clusters: (1) anterior skull base (22%; 12/55), (2) parieto-occipital junction (45%; 25/55) and (3) peri-torcular (33%; 18/55). Cluster analysis revealed no correlation between the location of the encephalocele with gender (χ2 (2, n = 91) = 3.86, p = 0.15). Compared to expected population frequencies, encephaloceles were relatively more common in Black, Asian and Other compared to White ethnicities. A falcine sinus was identified in 51% (28/55) of cases. Falcine sinuses were more common (χ2 (2, n = 55) = 6.09, p = 0.05) whilst brain herniation was less common (χ2 (2, n = 55) = .16.24, p < 0.0003) in the parieto-occipital location. CONCLUSION: This analysis revealed three predominant clusters for the location of encephaloceles, with the parieto-occipital junction being the most common. The stereotypic location of encephaloceles into anatomically distinct clusters and the coexistence of distinct venous malformations at certain sites suggests that their location is not random and raises the possibility of distinct pathogenic mechanisms unique to each of these regions.

A clinical clue toward recognition of split cord malformation type-I resembling meningocele in neonates.

This is a letter to share the clinical experience we had with neonates born with a specific feature of spina bifida. The lesion is like a meningocele containing skim amount of fluid, with a tiny dimple around the center of the cutaneous lesion which causes inward retraction of the dysplastic coverage. This feature is in favor of accompanied split cord malformation (SCM) type I, and the central nidus is in continuous with the dural sleeve around the bony septum of SCM. By recognition of this clinical clue, surgical repair can be planned to perform with appropriate provision, particularly foreseeing the amount of intraoperative bleeding and duration of anesthesia in the newborn patients.

Amniotic band syndrome with CNS involvement: a pediatric neurosurgeon's dilemma-a case series and literature review.

BACKGROUND: Amniotic band syndrome (ABS) is a rare congenital disease characterized by a broad spectrum of congenital anomalies resulting from the strangulated developing organ(s) by the detached fibrous amniotic band. The prevalence of CNS involvement in ABS is rare, but the mortality rate in these cases is high, while morbidity among the surviving patients is inevitable. CASE REPORT: Three-month-old male, 9-month-old female, and newborn female babies were presented with head lump(s), severe facial cleft, syndactyly, and finger amputation. The patient's head imaging confirmed meningoencephalocele as the cause of the head lump in 2 patients; meanwhile, a porencephalic cyst was identified as the origin of head lumps in the other patient. VP shunt placement surgery was performed as the initial management in 2 patients, while one patient directly underwent meningoencephalocele resection surgery. Craniofacial and limb reconstructions were planned as the follow-up management in all cases. Unfortunately, one patient died of complications from suspected aspiration, while another never returned for follow-up treatment. CONCLUSION: Here, we report 3 ABS cases with CNS involvement. Despite the severe disfigurement and disability, the inexistence of fatal malformation might lead to long-term survival. The treatment of malformation(s) that might predispose to another fatal condition and surgery(-ies) to improve functional outcomes and patient's social acceptability should be prioritized in managing the surviving ABS patients.

Posterior Surgical Ligation and Cyst Decompression -via Needle Puncture- of a Large Anterior Sacral Pelvic Meningocele Through Posterior Sacral Laminectomy.

The first documented description of an anterior sacral meningocele was Bryant's in 1823. Anterior sacral meningocele patients have constipation as a universal symptom; urinary incontinence is also common. All the symptoms are directly related to the pressure from a pelvic mass on adjacent structures. When the patient stands, a headache often develops because the spinal fluid pressure decreases as the meningocele sac fills. Finally, a scimitar-shaped sacrum on a neuroradiological anteroposterior plain assessment is pathognomonic. The coccyx may be absent, and the lower sacral laminae may be absent or incomplete. The surgical options for this rare clinical condition are still matter of debate.Anterior sacral meningocele is a pathology that lacks a current classification and neurosurgical therapeutic standards, even though a similar dynamic has been shown by the related traumatic pseudomeningocele. Anterior approaches (retro- and transperitoneal meningocele neck occlusion with internal cerebrospinal fluid (CSF) cyst drainage) and posterior approaches (posterior sacral laminectomy, dural sac ligation, and CSF cyst drainage) are the available surgical strategies.We now report the case of an adult patient for whom a posterior approach was suggested and performed and report her postoperative surgical follow-up. The surgical rationale is also discussed.

Bone fusion in transcele reconstruction of frontoethmoidal meningoencephalocele.

OBJECTIVE: In surgical correction of frontoethmoidal encephalocele with transcranial approach, advanced facilities are required. While with extracranial approach, though deemed as a safe option in area with limited facilities, procedure was associated with cerebrospinal fluid (CSF) leakage. In this case series, we evaluate the results of transcele reconstruction of frontoethmoidal encephalocele, our approach to reduce the incidence of CSF leaks by focusing on the closure of layers by its embryological derivatives, by its bone fusion. METHODS: A case series of 14 patients with various types of frontoethmoidal encephalocele who underwent surgery for defect closure using transcele approach between June 2015 and December 2018 was carried out. Surgery was done by a single surgeon in the Department of Neurosurgery of Cipto Mangunkusumo Hospital in Jakarta, Indonesia. We collected the data of intraoperative blood loss and any signs of infection and CSF leak during the patients' one-year follow up. Bone fusion in the defect was evaluated from 3D rendering of head CT scan that was performed before and in 1 year after surgery. RESULTS: The median percentage of intraoperative blood loss was 5.9% (0.5-18.7%). All 3D rendering of head CT post-surgery during 1 year follow up showed bone fusion and no patient experienced CSF leaks or CNS infections. CONCLUSIONS: This study showed that using transcele approach in frontoethmoidal reconstruction could give good bone fusion with minimal blood loss and no CSF leaks. We assumed that closure of the layers by its embryological derivative played an important part in bone fusion and in reducing the incidence of CSF leaks, although this finding has to be validated with large-scale studies.

Untreated meningomyelocele and squamous cell carcinoma: a case report and literature review.

BACKGROUND: Early closure of the meningocele, meningomyelocele, is essential to prevent complications such as hypothermia, infection in the postnatal period. But for some reasons, it is not always possible to repair early. The possibility of malign transformation should be considered in long-term due to nonhealing ulcers and cerebrospinal fluid (CSF) fistula and frequent infections in an adult patient with meningomyelocele. The possibility of conversion to malignancy in the control of an untreated meningomyelocele patient with (CSF) drainage should be especially kept in mind. CASE DESCRIPTION: A case is described of a malignant transformation at the site of a myelomeningocele in a 22-year-old woman. The lumbosacral region was deformed by a large meningomyelocele 10 cm in diameter, with areas of scar and ulcer. For 7 years prior to this presentation, the lesion was a large fistula in the roof of the open myelomeningocele. She underwent continuous CSF draining. A biopsy was done which revealed it as squamous cell carcinoma. CONCLUSION: Early closure of meningocele, meningomyelocele is essential to prevent complications such as hypothermia, infection in the postnatal period. Also, especially if there is continuous CSF exposure, the possibility of malignant change should be kept in mind in neglected cases presenting in an adult.

Evolution and Variations of the Ovine Model of Spina Bifida.

Spina bifida is the most common congenital anomaly of the central nervous system and the first non-fatal fetal lesions to be addressed by fetal intervention. While research in spina bifida has been performed in rodent, nonhuman primate, and canine models, sheep have been a model organism for the disease. This review summarizes the history of development of the ovine model of spina bifida, previous applications, and translation into clinical studies. Initially used by Meuli et al. [Nat Med. 1995;1(4):342-7], fetal myelomeningocele defect creation and in utero repair demonstrated motor function preservation. The addition of myelotomy in this model can reproduce hindbrain herniation malformations, which is the leading cause of mortality and morbidity in humans. Since inception, the ovine models have been validated numerous times as the ideal large animal model for fetal repair, with both locomotive scoring and spina bifida defect scoring adding to the rigor of this model. The ovine model has been used to study different methods of myelomeningocele defect repair, the application of various tissue engineering techniques for neuroprotection and bowel and bladder function. The results of these large animal studies have been translated into human clinical trials including Management of Meningocele Study (MOMS) trial that established current standard of care for prenatal repair of spina bifida defects, and the ongoing trials including the Cellular Therapy for In Utero Repair of Myelomeningocele (CuRe) trial using a stem cell patch for repair. The advancement of these life savings and life-altering therapies began in sheep models, and this notable model continues to be used to further the field including current work with stem cell therapy.

Prenatal and Neonatal Ultrasound and Magnetic Resonance Imaging Diagnosis of Sprengel's Deformity with Unusual Associations.

INTRODUCTION: Sprengel's deformity is a rare congenital anomaly of the shoulder rim. It is the most common congenital anomaly of the shoulder, associated with cosmetic deformity and abnormal shoulder function. Nonsurgical management can be considered for mild cases. Surgical intervention is indicated in moderate to severe cases with the goal of improving cosmetic appearance and function. The best surgical results are obtained in children aged 3-8 years. Correct diagnosis is very important because Sprengel's deformity can be accompanied by additional abnormalities, even in mild cases, and lack of a diagnosis delays proper treatment of the child. The severity of the defect may progress, so it is important to correctly identify children with Sprengel's deformity, even those with a mild form of the defect. CASE PRESENTATION: We report a case of prenatal sonographic diagnosis of Sprengel's deformity with additional features, as yet undescribed and missed - although visible - on prenatal magnetic resonance imaging (MRI). Cesarean delivery was performed due to preterm rupture of membranes, and a postnatal MRI confirmed the unusual constellation of Sprengel's anomaly with lateral meningocele, vestigial posterior meningocele, and lipoma tethering of the cord to the dural sac at the cervical-thoracic junction. CONCLUSION: Diagnosis of Sprengel's deformity is possible with prenatal ultrasound. Asymmetry of the cervical spine, discontinuity of the vertebral arch and abnormal vertebral bodies, as well as the asymmetric position of the shoulder blades with the presence of an omovertebral bone are signs that can help diagnose the defect.

Meningoencephalocele and supernumerary ectopic limb arising from the occipital bone in a Jacob sheep lamb.

This report describes the clinical, computed tomography, and magnetic resonance imaging findings for a Jacob sheep lamb diagnosed with meningoencephalocele and supernumerary ectopic limb. Key clinical message: This case demonstrates the utility of tomographic imaging in diagnosing congenital malformations in sheep and can be used to assess the extent of the lesion. This may help to determine any viable treatment, or, as in the case presented here, determine that the extent of the lesion precludes surgical intervention.

Méningoencéphalocèle et membre ectopique surnuméraire provenant de l'os occipital chez un agneau Jacob. Ce rapport décrit les résultats cliniques, de tomodensitométrie et d'imagerie par résonance magnétique d'un agneau de Jacob chez qui on a diagnostiqué une méningoencéphalocèle et un membre ectopique surnuméraire.Message clinique clé :Ce cas démontre l'utilité de l'imagerie tomographique dans le diagnostic des malformations congénitales chez le mouton et peut être utilisée pour évaluer l'étendue de la lésion. Cela peut aider à déterminer tout traitement viable ou, comme dans le cas présenté ici, à déterminer que l'étendue de la lésion exclut une intervention chirurgicale.(Traduit par Dr Serge Messier).

Case report: Meningoencephalocele and recurrent bacterial meningitis in chronic idiopathic intracranial hypertension.

BACKGROUND: Meningoencephalocele is a rare malformation caused by congenital and acquired lesions. The association between recurrent bacterial meningitis and meningoencephaloceles with cerebrospinal fluid (CSF) leak is reported in the literature. We report a rare case of meningoencephalocele secondary to chronic idiopathic intracranial hypertension as a result of hospitalization repeatedly for meningitis due to the lack of CSF leak. CASE PRESENTATION: This study presents a case of a patient with a decade of recurrent meningitis. With clinical symptoms and imaging examination with chronic idiopathic intracranial hypertension, this patient was diagnosed with meningoencephalocele. With the treatment of acetazolamide to decrease CSF product, the patient had no recurrence of meningitis over the 6-months follow-up period. CONCLUSION: In patients with recurrent intracranial infections but no history of immunodeficiency, cranial trauma, or neurosurgery, the possibility of meningitis should be considered appropriately, even in the absence of CSF otorrhea or rhinorrhea.

PLGA-Au-PFH-NPs-based Ultrasound Imaging in Detecting Fetal Spinal Deformities.

The study focused on the performance of ultrasound imaging in detecting fetal spinal deformities. First, the double emulsification method and the carbodiimide method were used to prepare the target Au-loaded nanorod phase-change nano-level contrast agent-PLGA-Au-PFH-NPs. After being characterized for physical and chemical properties, it was used in ultrasound imaging diagnosis. The results showed that the prepared PLGA-Au-PFH-NPs solution was a milky white suspension, the particle size detected by the laser particle sizer was (376.17±20.74) nm, and the Zeta potential was (-4.82±2.88) mV. Under the light microscope, it showed a spherical shape, uniform size distribution, and a very smooth surface. The encapsulation rate measured by the UV spectrophotometer was (80.63±4.82) %, and there was no significant difference in cell survival rate between different concentrations (P>0.05). Prenatal ultrasound in the observation group accurately diagnosed 10 cases with spinal deformities, and the diagnostic accuracy rate was 50%, including 5 cases of meningocele, 3 cases of invisible spina bifida, 1 case of myelomeningocele, and 1 case of hemivertebrae. In the control group, 7 cases were diagnosed correctly by conventional ultrasound, and the diagnosis accuracy rate was 35%, including 3 cases of meningocele, 3 cases of invisible spina bifida, and 1 case of hemivertebra. The diagnostic accuracy of the observation group was higher than that of the control group, and the difference was statistically significant (P<0.05). In conclusion, the prepared PLGA-Au-PFH-NPs had good physical and chemical properties. Ultrasound imaging based on the PLGA-Au-PFH-NPs had high accuracy in diagnosing fetal spinal deformities. To a certain extent, it provides a basis for clinical diagnosis of fetal spinal abnormality and some new ideas for ultrasound imaging diagnosis.

Early diagnosis of lateral meningocele syndrome in an infant without neurological symptoms based on genomic analysis.

Lateral meningocele syndrome is characterized by multiple lateral meningoceles with a distinctive craniofacial appearance, hyperextensibility of the skin, and hypermobility of the joints. The syndrome is caused by heterozygous truncating variants in the last exon, exon 33, of the NOTCH3 gene. Here, we present a 2-year-old girl for whom an early genomic analysis allowed us to recognize the presence of lateral meningoceles and to begin early monitoring of her condition for possible neurological complications. She had a characteristic facial appearance, hyperextensibility of the skin and mobility of the joints, and developmental delays. Given that lateral meningocele syndrome is a rare syndrome, the existence of lateral meningoceles is suspected only when the causative gene is detected by genetic testing. MRI scans are unlikely to be performed in infancy in the absence of neurological symptoms suggestive of meningoceles. No formal guidelines have been established for the neurosurgical indications for lateral meningocele syndrome. Given the features of hyperextensibility of the skin and hypermobility of the joints, lateral meningocele syndrome can be categorized as a connective tissue disease and may be progressive, as with the dural ectasia in Marfan syndrome and Loeys-Dietz syndrome. Watchful monitoring of dural ectasia may be warranted in patients with lateral meningocele syndrome.

Management of lateral meningocele syndrome in a child without neurological symptoms and literature review.

PURPOSE: Lateral meningocele syndrome (LMS) is a rare genetic connective tissue disorder which is associated with meningocele-related neurologic dysfunction. Several patients with LMS have been reported. But, guidelines for screening and treatment of LMS have not been established. METHOD AND RESULTS: We review the current knowledge of LMS in the article. Then, we describe a boy for whom a genomic analysis which allowed us to make a diagnosis of LMS and to begin monitoring of his condition for possible neurological complications. CONCLUSION: It would be difficult to make a diagnosis of LMS on the basis of clinical manifestations alone. The natural history of dural ectasia in patients with LMS needs to be better defined to establish surgical indications. Based upon the current literature, ventriculoperitoneal shunting (V-Ps) has been recommended as the first-line surgical treatment option for patients with symptomatic thoracolumbar meningoceles.

Post-traumatic intra-orbital meningoencephalocele in adults: technical note on a rare entity and review of the literature.

Post-traumatic orbital meningoencephaloceles related to orbital roof fractures are a challenging clinical entity because of their rarity and difficult differential diagnosis. We report a case of post-traumatic intra-orbital meningoencephalocele in a 69-year-old man, secondary to a likely trapdoor mechanism, treated with a modified one-piece orbitozygomatic craniotomy. We also performed an extensive literature review of traumatic Intra-Orbital Encephalocele related to Orbital Roof Fracture focused on adult patients on electronic databases including Scopus, MEDLINE/PubMed, and Google Scholar. Patient well recovered after surgery with immediate exophthalmos resolution and discharged without visual or neurological deficits. The literature review included 22 papers with a total of 28 patients: 22 males (78.6%) and 6 females (21.4%), with a median age of 34.7 years. Twenty-six patients (92.9%) reported ocular injuries, with associated intracranial complications in 16 cases (61.5%). Twenty-seven patients (96.4%) were surgically treated, 18 of those underwent unilateral or bilateral frontal approach. Most orbital roof fractures can be managed nanoperatively if asymptomatic. Indeed, when the intra-orbital volume decreases, for example due to an encephalocele, the intra-orbital pressure could increase and determine an orbital compartment syndrome. In our case, we performed a one-piece modified orbitozygomatic approach, which has several advantages in comparison to the frequent unilateral or bilateral frontal craniotomy like the better exposure of the brain and orbit and a minimum brain retraction.

Transcranial extradural subtemporal repair for sphenoid sinus lateral recess meningoencephalocele: technical note.

Cranial meningoencephalocele is a rare condition consisting of the herniation of meninges, CSF, and brain tissue through a cranial or skull base defect. Sphenoid sinus lateral recess meningoencephalocele is of particular interest due to the complex anatomy surrounding the bone defect and their demanding surgical management. In this technical note, we reported a step-by-step description of a rare case of sphenoid sinus lateral recess meningoencephalocele causing headache due to recurrent cerebrospinal fluid leak treated with a subtemporal craniotomy with extradural middle cranial fossa drilling and meningoencephalocele removal with multilayer reconstruction. The transcranial route is a safe and effective treatment for sphenoid sinus lateral recess meningoencephalocele repair. The subtemporal extradural approach allows for an optimal exposure of the relevant anatomy minimizing risks and improving the possibility to perform an effective multilayer skull base reconstruction.

Retained Medullary Cord Associated with Terminal Myelocystocele and Intramedullary Arachnoid Cyst.

INTRODUCTION: The retained medullary cord (RMC) is a newly defined entity of closed spinal dysraphism that is thought to originate from regression failure of the medullary cord during the last phase of secondary neurulation. The terminal myelocystocele (TMC) is an unusual type of closed spinal dysraphism, characterized by localized cystic dilatation of the terminal part of the central canal that then herniates through a posterior spinal bifida. The co-occurrence of RMC and TMC is extremely rare. CASE PRESENTATION: We treated a baby girl with a huge sacrococcygeal meningocele-like sac with two components. Untethering surgery and repair surgery for the sac revealed that RMC, associated with intramedullary arachnoid cyst (IMAC), was terminated at the bottom of the rostral cyst, forming the septum of the two cystic components, and the caudal cyst was TMC derived from the central canal-like ependymal lining lumen (CC-LELL) of the RMC at the septum. IMAC within the RMC communicated with TMC, and both contained xanthochromic fluid with the same properties. CONCLUSION: We speculated that the mass effect of the coexistent IMAC impeded the flow of cerebrospinal fluid in the CC-LELL within the RMC and eventually formed a huge TMC. In surgical strategies for such complex pathologies, it is important to identify the electrophysiological border between the functional cord and nonfunctional RMC and the severe RMC to untether the cord, as with a typical or simple RMC.