Primary Intracranial Squamous Cell Carcinoma in the Brain Stem with a Cerebellopontine Angle Epidermoid Cyst

Primary intracranial squamous cell carcinoma is extremely rare, with most cases arising from a preexisting benign epidermoid cyst. We report a rare case of primary intracranial squamous cell carcinoma in the brain stem with a cerebellopontine angle (CPA) epidermoid cyst. A 72-year-old female suffered from progressive left hemiparesis, difficulty in swallowing, and right hemifacial numbness. Diffusion-weighted magnetic resonance imaging revealed a high signal intensity (SI) lesion in the CPA region and an intra-axially ring-enhanced cystic mass in the right brain stem with low SI. Whole-body positron emission tomography showed no evidence of metastatic disease. The histological findings revealed a typical epidermoid cyst in the CPA region and a squamous cell carcinoma in the brain stem. We speculate that the squamous cell carcinoma may have been developed due to a chronic inflammatory response by the adjacent epidermoid cyst. The patient underwent a surgical resection and radiotherapy. After 12 months, she had no evidence of recurrence.     

A giant retroclival Rathke’s cleft cyst

Rathke’s cleft cyst (RCC) is a rare sellar tumor that can extend to the retroclival region, resulting in brain stem compression. We report a male with short stature who experienced repeated syncope due to compression of the brain stem by a giant retroclival RCC. MRI revealed a large homogeneous sellar tumor with anterior displacement of the pituitary gland that extended to the left retroclival space. The tumor differed from ordinary RCCs because of its unusual clinical presentation, the direction of extension, and its imaging characteristics. The retromastoid surgical approach was used for cyst marsupialization. Intraoperative appearance and histological examination confirmed the diagnosis. A follow-up MRI, 2 years after resection of the cyst, showed no recurrence.     

Recurrent intrinsic brain stem epidermoid cyst

The authors report the case of a 14-month-old baby boy with an epidermoid cyst located entirely within the pons and medulla, without an exophytic component. The lesion was examined by computed tomography and magnetic resonance imaging. The child was operated upon three times after two recurrences of the lesion. A suboccipital, subtonsillar approach was used for the first and second procedures and a transtemporal approach for the last one. Excision was thought to be complete the first time, since a solid tumor was found and removed in a large cyst. The cyst wall was not identified. No tumor was found during the second procedure despite recurrence of the cyst, which was drained without an attempt to remove the cyst wall. Finally the cyst recurred with a large tumor in the cyst wall which was again totally removed. Consistent with the high mortality of brain stem epidermoid cysts in the literature, the child eventually died. The therapeutic problems, surgical options, and consequences are discussed.     

颅内上皮样囊肿的临床特征与显微手术入路探讨

目的为了提高颅内上皮样囊肿（ＩＥＣ）的诊断水平与手术治疗效果。方法总结分析２１８例ＩＥＣ的临床征象、诊断方式、显微手术入路与疗效。结果２０３例肿瘤获全切除；１５例因肿瘤包膜与丘脑或脑干粘连紧密而行次全切除。５例于手术后２周内因脑干缺血、水肿或肺部感染死亡。１７６例获长期随访（平均５．６年），有１７０例恢复良好；３例肿瘤有复发，需行再次手术切除。结论采用ＣＴ或ＭＲＩ进行诊断、合理选择手术入路并应用显微手术治疗ＩＥＣ，是行之有效的方法。     

Long-term expansion of human foetal neural progenitors leads to reduced graft viability in the neonatal rat brain

We previously reported that early passage human foetal neural progenitors (hFNPs) survive long-term in the rodent host brain whereas late passage cells disappear at later post-graft survival times. The extent to which this finding is related to changes in the expanded FNPs or in the adult host brain environment was not determined. Here we report the effect of expanding hFNPs for different periods of time in vitro on their ability to survive transplantation into the neonatal rat hippocampus, a generally more permissive environment than the adult rat brain. After 2 and 8 weeks in vitro, transplanted hFNPs formed large grafts, most of which survived well until at least 12 weeks. However, following continued expansion, hFNPs formed smaller grafts, and cells transplanted after 20 weeks expansion produced no surviving grafts, even at early survival times. To determine whether this could be due to a dilution of "true" neural stem cells through more differentiated progeny over time in culture, we derived homogeneous neural stem (NS) cells grown as a monolayer from the 8 week expanded hFNPs. These cells homogeneously expressed the neural stem cell markers sox-2, 3CB2 and nestin and were expanded for 5 months before transplantation into the neonatal rat brain. However, these cells exhibited a similar survival profile to the long-term expanded FNPs. These results indicate that, while the cellular phenotype of neural stem cells may appear to be stable in vitro using standard markers, expansion profoundly influences the ability of such cells to form viable grafts.     

Clinical characteristics and diagnostic imaging of epidermoid tumors

Epidermoid tumors are rare, benign congenital lesions which typically present between the third and fifth decades of life. They are thought to originate from ectodermal cells misplaced during neural tube formation and separation. While epidermoids may present anywhere in the cranial vault, they are characteristically located intradurally and in a paramedian position within the cerebellopontine angle and parasellar regions. Although imaging results may vary depending upon cystic content, CT scanning generally reveals a well-circumscribed, nonenhancing, lobulated, hypodense mass. They are hypointense on T1-weighted MRI, and hyperintense on T2-weighted MRI, diffusion-weighted imaging and fluid-attenuated inversion recovery sequences. The use of appropriate neuroimaging should be utilized to differentiate epidermoids from other intracranial lesions. While gross total resection of these tumors is the definitive treatment to prevent recurrence and aseptic meningitis, a subtotal resection may be necessary to preserve neurological function.     

Intractable Hiccup as the Presenting Symptom of Cavernous Hemangioma in the Medulla Oblongata: A Case Report and Literature Review

A case of intractable hiccup developed by cavernous hemangioma in the medulla oblongata is reported. There have been only five previously reported cases of medullary cavernoma that triggered intractable hiccup. The patient was a 28-year-old man who was presented with intractable hiccup for 15 days. It developed suddenly, then aggravated progressively and did not respond to any types of medication. On magnetic resonance images, a well-demarcated and non-enhancing mass with hemorrhagic changes was noted in the left medulla oblongata. Intraoperative findings showed that the lesion was fully embedded within the brain stem and pathology confirmed the diagnosis of cavernous hemangioma. The hiccup resolved completely after the operation. Based on the presumption that the medullary cavernoma may trigger intractable hiccup by displacing or compression the hiccup arc of the dorsolateral medulla, surgical excision can eliminate the symptoms, even in the case totally buried in brainstem.     

A giant intradiploic epidermoid cyst with perforation of the dura and brain parenchymal involvement

A patient with a long-standing intradiploic epidermoid cyst with perforation of the dura and brain parenchymal involvement is reported. A 69-year-old man, who had previously presented with a subcutaneous mass on the left frontoparietal scalp, developed a sudden grand mal seizure. Magnetic resonance imaging showed a well-defined mass in the frontoparietal scalp with destruction of the skull. Penetration of the dura allowed for communication with the intracranial structures. Surgical resection and cranioplasty were performed. There were no well-defined margins in the deep portion and the mass was subtotally removed. Histological examination showed that the cystic structure was lined by squamous epithelium containing laminated keratin material. The pathologic findings were consistent with the diagnosis of an epidermoid cyst.     

Intracranial neurenteric cyst: A rare cause of chemical meningitis

Intracranial neurenteric cysts are exceedingly rare congenital intracranial lesions that result from disorder of gastrulation. Still, more rarely, the cyst contents may leak into the CSF and give rise to recurrent episodes of chemical meningitis. We present a case of chemical meningitis due to a leaking posterior fossa neurenteric cyst in a young female, with emphasis on its imaging features. The final diagnosis was achieved by sufficiently characteristic imaging features; histopathologic documentation could not be achieved as the patient denied surgery.     

Paraparesis caused by a bilateral cervical synovial cyst

We describe a 64-year-old man who suffered from rapidly progressive paraparesis. At operation the cervical cord of the patient was found to be displaced anteriorly due to compression caused by an epidural synovial cyst. The cyst was located bilaterally on the dorsolateral aspect of both CVII facet joints. The rapid development of paraparesis in this patient can, thus, be explained by the enlargement of the cyst on both sides of the spinal cord. After microsurgical removal of the cystic tumor, the recovery of the patient was good. Cervical epidural cysts are extremely rare, and only anecdotal cases have been reported in the literature. Among all previously described patients the present case is unique due to the bilateral location of the cyst.     

Erfahrungsgesteuerte neuronale Plastizität Bedeutung für Pathogenese und Therapie psychischer Erkrankungen

Whereas the basic wiring of the mammalian central nervous system is genetically predefined, its fine tuning throughout different phases of infancy, childhood, and adulthood are highly experience-dependent. There is growing evidence from a variety of experimental data that juvenile experience and learning events modulate the functional maturation of the brain, thereby shaping the neuronal substrate for the development of intellectual and socioemotional capacities. Since early experiences occur during phases of elevated neuronal and synaptic plasticity, they induce an "imprinting" of synaptic connectivity and neural circuitry in the infant brain. Results from experimental research support the hypothesis that impoverished intellectual stimulation and traumatic socioemotional experience during early childhood may impair the formation of functional brain pathways, in particular of the limbic circuits, which play a major role in emotional behavior and learning. Such defective systems, representing functional "scars" in the brain, may be the neuronal basis of a variety of mental disorders and clinical symptoms caused by early stressful psychosocial environments. A basic thesis of this paper is that mechanisms involved in neuronal learning and memory are not only used and reused in structuring the CNS during the initial establishment of connections in the immature brain but also can be employed in molding personality and behavior during psychotherapy in adulthood.     

Endoscopic management of posterior fossa arachnoid cyst in an adult: case report and technical note

The authors report a case of large arachnoid cysts of the posterior fossa treated by endoscopic surgery. A 40-year-old man was admitted with a 3-month history of headache and progressive gait imbalance, with no significant medical history. At the time of admission, neurological examination revealed no abnormalities except for tandem imbalance. Brain computerized tomography (CT) scan and magnetic resonance imaging (MRI) revealed a posterior fossa arachnoid cyst (PFAC) causing brain stem compression accompanied by hydrocephalus. The patient was treated by endoscopic fenestration of the cyst with a paramedian suboccipital transcortical approach. Postoperatively the patient's complaints showed improvement and he was discharged with no complications. Follow up MRI showed a decrease in the cyst's size and the hydrocephalus with decompression of the brain stem.     

神经干细胞及其在脑修复中的可能应用

成年哺乳动物脑内存在有能分化成神经元或神经胶质的神经干细胞,这种神经前体细胞一般位于脑室壁部位。从胎脑分离下来的神经前体细胞能在体外分裂并进一步分化成神经元和胶质细胞,许多包括生长因子在内的活性物质或分子结构参与这一分化过程并决定这些细胞的转归;从成年脑中也能分离出有繁殖能力的细胞,当这些存在于中枢神经系统内的干细胞（即多潜能细胞）和具有明确前景的前体细胞（神经母细胞和胶质母细胞）遇到与胚胎时期相同因子的影响时也会分裂、分化。由于在体外培养状况下难以提供神经前体细胞分化繁殖的所有条件,故将其植入发育中或成年中枢神经系统特定部位的做法是研究神经干细胞特性,特别是研究决定其分化微环境的有效办法。对神经干细胞的研究,为进一步探讨神经元的发生、迁移、分化和诊治多种神经疾患提供了新的机遇。     

Injury-induced neurogenesis in Bax-deficient mice: evidence for regulation by voltage-gated potassium channels

Adult neural stem and progenitor cells may help remodel the brain in response to injury. The pro-apoptotic molecule Bax has recently been identified as a key player in adult neural stem cell survival. In Bax-deficient mice that have undergone traumatic brain injury, we find increased numbers of neural progenitor cells in the dentate gyrus and improved remodeling of the hippocampus. Exogenous potassium chloride mimics spreading depression (SD)-like events in vitro, and Bax-deficient neural stem cells proliferate in response to these events more robustly than wild-type neural stem cells. Selective potassium channel blockers interrupt SD-mediated stimulation of stem cells. In addition, the potassium channel Kv4.1 is expressed within neural stem and progenitor cells in the dentate gyrus and is increased in Bax-deficiency. These data suggest that the neuroprotection observed after injury in Bax-deficiency may be due to increased neurogenesis via activation of the Kv4 family of potassium channels.     

Spontaneous regression of an epidermoid cyst of the cavernous sinus

Epidermoid cysts are rare lesions in the pediatric population. The natural history of epidermoids is usually that of slow growth, although rupture and cases of malignant transformation have been reported. Spontaneous regression of an intracranial epidermoid cyst has not previously been described to our knowledge. We present a 3-year-old boy who presented with severe vertigo. MRI was performed which revealed a 2 cm non-enhancing lesion in the right cavernous sinus. The lesion was T1-hypoinsense, T2-hyperintense, and with evidence of restricted diffusion, consistent with an epidermoid cyst. The patient was followed with annual MRI studies over the next 3 years, demonstrating progressive reduction in the size of the lesion over time, with complete resolution after 3 years. The child’s symptoms also resolved during this period. Long-term follow-up imaging at 5 years showed no evident lesion. To our knowledge, this is the first report documenting spontaneous regression of an intracranial epidermoid cyst. While isolated, this finding demonstrates the potential for involution of epidermoids and lends support to the clinical practice of careful observation of these lesions, especially when located in areas associated with high potential surgical morbidity. Importantly, the novelty of this observation suggests a need for further study to better elucidate the underlying mechanism of this regression.     

Absence of CCL2 is sufficient to restore hippocampal neurogenesis following cranial irradiation

Cranial irradiation for the treatment of brain tumors causes a delayed and progressive cognitive decline that is pronounced in young patients. Dysregulation of neural stem and progenitor cells is thought to contribute to these effects by altering early childhood brain development. Earlier work has shown that irradiation creates a chronic neuroinflammatory state that severely and selectively impairs postnatal and adult neurogenesis. Here we show that irradiation induces a transient non-classical cytokine response with selective upregulation of CCL2/monocyte chemoattractant protein-1 (MCP-1). Absence of CCL2 signaling in the hours after irradiation is alone sufficient to attenuate chronic microglia activation and allow the recovery of neurogenesis in the weeks following irradiation. This identifies CCL2 signaling as a potential clinical target for moderating the long-term defects in neural stem cell function following cranial radiation in children.     

Aberrant signaling pathways in medulloblastomas: a stem cell connection

Medulloblastoma is a highly malignant primary tumor of the central nervous system. It represents the most frequent type of solid tumor and the leading cause of death related to cancer in early childhood. Current treatment includes surgery, chemotherapy and radiotherapy which may lead to severe cognitive impairment and secondary brain tumors. New perspectives for therapeutic development have emerged with the identification of stem-like cells displaying high tumorigenic potential and increased radio- and chemo-resistance in gliomas. Under the cancer stem cell hypothesis, transformation of neural stem cells and/or granular neuron progenitors of the cerebellum are though to be involved in medulloblastoma development. Dissecting the genetic and molecular alterations associated with this process should significantly impact both basic and applied cancer research. Based on cumulative evidences in the fields of genetics and molecular biology of medulloblastomas, we discuss the possible involvement of developmental signaling pathways as critical biochemical switches determining normal neurogenesis or tumorigenesis. From the clinical viewpoint, modulation of signaling pathways such as TGFβ, regulating neural stem cell proliferation and tumor development, might be attempted as an alternative strategy for future drug development aiming at more efficient therapies and improved clinical outcome of patients with pediatric brain cancers.     

The orbicularis oculi reflex: pathologic studies in childhood

The orbicularis oculi reflex was studied in 12 children with intrinsic brain stem gliomas and in six children with other posterior fossa pathology. The results were compared with previously established childhood normal values. Seventy-eight percent of the children demonstrated a pathologic alteration of the reflex comparable to reported results in adult patients. The orgicularis oculi reflex test in childhood in a relatively simple and risk-free procedure in the evaluation of brain stem disease in childhood.     

Lumbar facet cyst resolution following anterior interbody fusion

Facet cysts are a relatively common source of neural compression in the lumbar spine. Open decompression and fusion are frequently used to treat the stenosis and instability associated with this pathology. Recently, anterior lumbar interbody fusion (ALIF) has increased in popularity for the treatment of lumbar degenerative conditions. ALIF may achieve indirect decompression of the neural elements with less surgical morbidity than conventional open approaches. To date, there are no published reports describing the use of indirect decompression or interbody fusion for the treatment of facet cysts. We report a patient who developed an L4-L5 facet cyst secondary to degenerative changes and spondylolisthesis. ALIF with posterior instrumentation was used to address his condition. Six months after surgery, the patient had complete resolution of his symptoms. MRI revealed complete resolution of the facet cyst. This patient provides previously unreported evidence that interbody fusion alone may result in facet cyst resolution. Clinical studies are needed to evaluate if interbody fusion can consistently relieve the symptoms associated with facet cysts without the use of direct decompression.     

Desarrollo de un linfoma cerebral con relación a un quiste epidermoide de larga evolución

IntroductionEpidermoid cysts (EC) are benign and slow growing lesions. A primary brain lymphoma development related to a EC is presented, second case described in literature.Case presentationA woman 40 years old, harbouring a EC for more than 20 years, develops a fast growing brain lesion next to the EC. Surgery was performed and diagnosis was primary diffuse B cells lymphoma.DiscussionMalignant transformation of EC has been described, usually to squamous cells carcinoma, and much less frequently, to another tumours. Inflammatory mechanisms have been advocated to explain this evolution. Chronic inflammation and lymphoma genesis are related, and this could be the mechanism behind this rare evolution of an EC.ConclusionsEven being benign lesions, EC can develop malignant tumours due to the chronic inflammation secondary to them.