Syringomyelia associated with a posterior fossa cyst. Illustration of two cases

Syringobulbia associated with posterior fossa meningioma: a review of the literature

PURPOSE

Syringomyelia can be defined as a degenerative, progressive and chronic spinal cord disease. Its association with tumors of the posterior cranial fossa (PCF) is a rare condition.

METHODS

The authors report a rare case of syringobulbia consequent to a meningioma originating from PCF in a 17-year-old female, discussing the pathogenetic mechanism of development and the resolution of the syrinx cavity after surgical procedure.

RESULTS

The postoperative period was uneventful without complications. At 6-month follow-up, MRI revealed complete tumor removal with resolution of the syrinx cavity.

CONCLUSIONS

In cases of syringomyelia and tonsillar herniation associated with PCF meningioma, the tumor resection allows to eliminate the mass effect and increases the size of the posterior fossa with the progressive ascent of the cerebellar tonsils and the consequent reduction of their downward movement with systolic pulsation. The re-establishment of a normal anatomical condition led to the gradual disappearance of syrinx and hydrocephalus.

Associated disorders of Chiari Type I malformations: a review

A single pathophysiological mechanism of Chiari Type I malformations (CM-I) has been a topic of debate. To help better understand CM-I, the authors review disorders known to be associated with CM-I. The primary methodology found among most of them is deformation of the posterior cranial fossa, usually with subsequent decrease in volume. Other mechanisms exist as well, which can be categorized as either congenital or acquired. In understanding the relationship of such disorders with CM-I, we may gain further insight into the process by which cerebellar tonsillar herniation occurs. Some of these pathologies appear to be true associations, but many appear to be spurious.

Supracerebellar arachnoid cyst – A rare cause of acquired Chiari I malformation

Chiari I malformation (CM) associated with a cervico-thoracic syrinx due to supracerebellar arachnoid cyst has not been reported in the literature. We report such a case, managed by fenestration of the arachnoid cyst and foramen magnum decompression (FMD), aiming to reduce the inferiorly directed pressure on the cerebellum and eliminate the craniospinal pressure dissociation respectively. Imaging done post-operatively showed upward displacement of the cerebellar tonsils with a decompressed craniovertebral junction and disappearance of the syrinx.

Tonsillar herniation and cervical syringomyelia in association with posterior fossa tumors in children: a case-based update

BACKGROUND

Posterior fossa tumors most commonly occur in children. They frequently present with raised intracranial pressure and may have tonsillar herniation. The symptomatology is predominantly directed towards the tumor. The occurrence of syringomyelia in such cases is most unusual. Symptomatic syringomyelia is rare.

CASE REPORT

We describe a case of a pilocytic astrocytoma of the cerebellum in a 13-year-old girl who presented with clinical features of progressively worsening raised intracranial pressure and secondary tonsillar herniation and cervical syringomyelia. Magnetic resonance (MR) imaging showed a large midline inhomogenously enhancing vermian tumor causing moderate obstructive hydrocephalus. In addition, the cerebellar tonsils herniated down to the C2 level, and there was a centrally located syrinx from C2-T1. The tumor was resected through a suboccipital craniectomy. At follow-up after 3 months, MR imaging demonstrated total resolution of tonsillar herniation and cervical syringomyelia.

CONCLUSIONS

The occurrence of tonsillar herniation and syringomyelia in association with a slow growing benign tumor like pilocytic astrocytoma of the cerebellum is uncommon. The blockade of normal cerebrospinal fluid circulation pathway at the foramen magnum is the crucial factor. Surgical extirpation of the tumor restores the normal cerebrospinal fluid circulation at the foramen magnum and produces an excellent outcome. The need for an additional surgical procedure for treatment of associated tonsillar herniation and syringomyelia can be avoided. Volumetric assessment of the posterior fossa may provide a better understanding of the pathophysiology of syringomyelia in such patients.

Resolution of tonsillar herniation and cervical syringomyelia following resection of a large petrous meningioma: case report and review of literature

We describe a case of a large, petrous meningioma associated with tonsillar herniation and cervical syringomyelia. The patient, a 53-year-old woman, had a 6-month history of a dull, aching pain in the occipital region associated with numbness in the right C2 dermatome and left gaze evoked nystagmus. Magnetic resonance imaging (MRI) revealed a large tumor in the right posterior fossa associated with moderate supratentorial hydrocephalus. Secondary tonsillar herniation and cervical syringomyelia extending from C2 to C6 were also identified. The tumor, later confirmed to be a meningioma originating from the petrous region, was resected completely via a retrosigmoid approach. Postoperative MRI demonstrated total resolution of the tonsillar herniation and cervical syringomyelia. The radiological features, potential pathophysiological mechanisms, and treatment strategies are discussed in relation to the recent literature.

Trigeminal neurinoma associated with Chiari malformation and syringomyelia

We report a 36 year-old woman who presented with headaches and hypoesthesia of the face. MRI revealed a large dumbbell shaped trigeminal neurinoma extending into both the middle and the posterior cranial fossae. In addition, there was a Chiari I malformation and syringomyelia. Within two months of tumor resection, both the Chiari malformation and the syringomyelia resolved. The association of an intracranial space-occupying lesion with Chiari malformation and syringomyelia is reviewed.

Association of the Adult Chiari Malformation and Idiopathic Intracranial Hypertension: more than a coincidence

There are significant similarities between the Adult Chiari Malformation (ACM) and Idiopathic Intracranial Hypertension (IIH). They include similar demographics, clinical presentation, and response to treatment. There is an eightfold increase in the incidence of significant tonsillar herniation in patients with IIH. Based on these findings and our observation in a subgroup of patients with failed ACM decompression, we suggest that these disorders are interrelated in a group of patients. The physiopathology is that of craniocephalic disproportion, i.e., a disproportion between the skull and the brain, due to a small skull or posterior fossa (like in ACM) and/or an engorged brain (like in IIH). This will occasionally lead to tonsillar ectopia. The craniocephalic disproportion will alter the brain compliance and lead to the symptomatology.

Endoscopic fenestration of posterior fossa arachnoid cyst for the treatment of presyrinx myelopathy--case report

A 32-year-old man presented with an arachnoid cyst of the posterior fossa manifesting as cervical syringomyelic myelopathy. Magnetic resonance (MR) imaging demonstrated edematous enlargement and T2 prolongation of the cervical spinal cord, indicating a "presyrinx" state. MR imaging showed the inferior wall of the cyst, which disturbed cerebrospinal fluid (CSF) pulsatile movement between the intraspinal and intracranial subarachnoid spaces. The cyst wall was fenestrated with a neuroendoscope. The presyrinx state and the CSF movement improved. Posterior fossa arachnoid cyst, as well as Chiari malformation, can cause CSF flow disturbance at the craniocervical junction and syringomyelia. Endoscopic fenestration is less invasive than foramen magnum decompression and should be the procedure of choice.

Definition of the adult Chiari malformation: a brief historical overview

With the widespread use of newer neuroimaging techniques and modalities, significant tonsillar herniation is being diagnosed in more than 0.5% of patients, some of whom are asymptomatic. This puts the definition of the adult Chiari malformation to the test. The author provides a historical review of the evolution of the definition of the adult Chiari malformation in the neurosurgery, radiology, and pathology literature.

Resolution of tonsillar herniation and syringomyelia after supratentorial tumor resection: case report and review of the literature

OBJECTIVE AND IMPORTANCE

The pathophysiological features of syringomyelia are not yet entirely understood. We present a case of a supratentorial mass causing tonsillar herniation and syringomyelia.

CLINICAL PRESENTATION

A 51-year-old woman underwent magnetic resonance imaging for evaluation of progressive headaches. A large parieto-occipital mass was revealed. Herniation of the cerebellar tonsils and a cervical syrinx were also noted.

INTERVENTION

A craniotomy was performed without incident. After tumor resection, the tonsils ascended and the syrinx resolved in a 1-year period.

CONCLUSION

This case highlights the importance of tonsillar herniation in the pathogenesis of syringomyelia. "Acquired" Chiari malformations and syringomyelia attributable to supratentorial masses may be treated by mass resection alone, without the need for foramen magnum decompression.

Syringomyelia persistence after Chiari decompression as a result of pseudomeningocele formation: implications for syrinx pathogenesis: report of three cases

OBJECTIVE AND IMPORTANCE

We present the cases of three patients in whom pseudomeningocele (PSM) formations after posterior fossa decompression of hindbrain herniations (Chiari I malformations) were associated with persistence of syringomyelia. The physiological importance of correcting this complication has not been previously described.

CLINICAL PRESENTATION

We identified three patients who developed suboccipital PSMs after undergoing posterior fossa decompression for hindbrain herniations and syringomyelia. All three patients experienced persistence of their symptoms and their syringomyelia, despite adequate posterior fossa decompression.

TECHNIQUE

Subsequent exploration revealed cerebrospinal fluid leaking either from the dural suture line (one patient) or from perforations found within the bed of a polyglactin mesh dural graft (two patients). Correction of the PSM resulted in resolution of both the syringomyelia and the symptoms in all three patients.

DISCUSSION

The persistence of syringomyelia in the presence of a PSM may be the result of dissipation of the cerebrospinal fluid systolic pressure wave into the distensible PSM cavity. This phenomenon suggests that the cerebrospinal fluid pressure exerted on the spinal cord surface favors resolution of the syrinx cavity.