Ventral Intrameningeal Cyst Treatment and Management: Technical Note.

BACKGROUND: Intrameningeal cysts are rare lesions without definitive etiologies that can involve the dura or arachnoid mater. Spinal arachnoid cysts have been described, and several different etiologies have been hypothesized. This includes one-way valve mechanisms, traumatic herniation of arachnoid through the dura, and abnormal arachnoid membrane proliferation. To the authors' knowledge, no such descriptions exist regarding purely dural-based cystic lesions; however, the authors hypothesize similar mechanisms may be involved. Most notably, a traumatic injury to the dura leading to a one-way valve mechanism may allow for egress of cerebrospinal fluid between the dural layers, splitting them open. This progressive enlargement can lead to displacement of neural elements and subsequent neurological compromise. METHODS: We describe a 17-year-old girl who presented with progressive neck and back pain, left upper-extremity numbness, bilateral lower-extremity weakness, paresthesias, and numbness without obvious etiology despite an extensive neurologic investigation. She had undergone conservative management options including multiple medications, physical and chiropractic therapy, and epidural steroid injections. Computed tomography myelography revealed a cerebrospinal fluid leak into the lumbar epidural space for which surgical exploration was performed. Despite utilizing fluoroscopy and intrathecal fluorescein, no leak source was identified. Fluid collection was found contained within the dural layers rather than the epidural space. RESULTS: An intracystic blood patch was performed with near-complete resolution of the lesion by 6-week follow-up and near-complete return of neurologic function. CONCLUSIONS: Ventral panspinal cysts are an exceedingly rare cause of radiculopathy and myelopathy that can be resolved by an intracystic blood patch.

WNT1-associated osteogenesis imperfecta with atrophic frontal lobes and arachnoid cysts.

A rare form of osteogenesis imperfecta (OI) caused by Wingless-type MMTV integration site family 1 (WNT1) mutations combines central nervous system (CNS) anomalies with the characteristic increased susceptibility to fractures. We report an additional case where arachnoid cysts extend the phenotype, and that also confirms the association of intellectual disabilities with asymmetric cerebellar hypoplasia here. Interestingly, if the cerebellum is normal in this disorder, intelligence is as well, analogous to an association with similar delays in a subset of patients with sporadic unilateral cerebellar hypoplasia. Those cases typically appear to represent vascular disruptions, and we suggest that most brain anomalies in WNT1-associated OI have vascular origins related to a role for WNT1 in CNS angiogenesis. This unusual combination of benign cerebellar findings with effects on higher functions in these two situations raises the possibility that WNT1 is involved in the pathogenesis of the associated sporadic cases as well. Finally, our patient reacted poorly to pamidronate, which appears ineffective with this form of OI, so that a lack of improvement is an indication for molecular testing that includes WNT1.

Magnetic resonance imaging provides evidence of glymphatic drainage from human brain to cervical lymph nodes.

Pre-clinical research in rodents provides evidence that the central nervous system (CNS) has functional lymphatic vessels. In-vivo observations in humans, however, are not demonstrated. We here show data on CNS lymphatic drainage to cervical lymph nodes in-vivo by magnetic resonance imaging (MRI) enhanced with an intrathecal contrast agent as a cerebrospinal fluid (CSF) tracer. Standardized MRI of the intracranial compartment and the neck were acquired before and up to 24-48 hours following intrathecal contrast agent administration in 19 individuals. Contrast enhancement was radiologically confirmed by signal changes in CSF nearby inferior frontal gyrus, brain parenchyma of inferior frontal gyrus, parahippocampal gyrus, thalamus and pons, and parenchyma of cervical lymph node, and with sagittal sinus and neck muscle serving as reference tissue for cranial and neck MRI acquisitions, respectively. Time series of changes in signal intensity shows that contrast enhancement within CSF precedes glymphatic enhancement and peaks at 4-6 hours following intrathecal injection. Cervical lymph node enhancement coincides in time with peak glymphatic enhancement, with peak after 24 hours. Our findings provide in-vivo evidence of CSF tracer drainage to cervical lymph nodes in humans. The time course of lymph node enhancement coincided with brain glymphatic enhancement rather than with CSF enhancement.