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

Childs Nerv Syst Syringobulbia associated with posterior fossa meningioma: a review of the literature Mattia Del Maestro Danilo De Paulis Alessandro Ricci Francesco Di Cola Renato Galzio 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-yearold 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. Syringomyelia; Posterior cranial fossa; Meningioma; CSF circulation - The syringomyelic cavity is a degenerative, progressive, and chronic spinal cord disease. Sometimes, the cavity may extend at the level of the medulla oblongata, causing a syringobulbia [22]. Syringomyelia is most commonly secondary to a Chiari malformation [22]. Its association with tumors of the posterior cranial fossa (PCF) is a rare condition, with few cases described in literature of epidermoids [11, 27], medulloblastomas [21, 28], gliomas [28], metastases [28], synovialomas [21], cysts [3, 5, 8, 10, 18, 29, 35], gangliocytomas [24], dysembryoplastic tumors [34], and meningiomas (Table 1) [2, 6, 7, 9, 12, 13, 1921, 28] The authors present a case of syringobulbia secondary to a meningioma of the PCF, reviewing the pertinent literature and discussing surgical management and the potential pathogenetic mechanism. A 17 year-old female, with recurrent episodes of dizziness, paresthesia in left trigeminal regions, and headaches, from 1 month, began to suffer from neck pain, loss of balance, numbness, and dysesthesia in the upper limbs. She presents a horizontal right gaze-evoked nystagmus, left hearing loss, and left swinging at the Rombergs test. Brain and spinal magnetic resonance imaging (MRI) revealed a large left sighted extra-axial tumor in the PCF, associated with supratentorial hydrocephalus. The cerebral tonsils were herniated down through the foramen magnum, and a syrinx was centrally located from medulla oblongata to C7 (Fig. 1). The patient underwent to a left retrosigmoid craniectomy with total tumor resection. The histopathological diagnosis was a fibrous meningioma (WHO grade 1). Fig. 1 Preoperative brain MRI in axial (a) and sagittal (b) T1-weighted images with Gadolinium, revealed a left sighted extra-axial tumor in the PCF, originating from the petrous bone, measuring 656.5 cm; the preoperative cervico-dorsal MRI in sagittal T2-weighted image showed cerebral tonsils herniated down through the foramen magnum and a syrinx from medulla oblongata to C7 (c) The postoperative period was uneventful without complications. At 6-month follow-up, MRI revealed complete tumor removal with resolution of the syrinx cavity (Fig. 2). From 1993 to 2013, only ten reports, accounting for a total of 11 meningiomas of the PCF associated with tonsillar herniation and syringomyelia, have been described in literature [2, 6, 7, 12, 13, 1921, 28]. The average age of the patients is 42 years with the female prevalence of 10:1. In range of solid tumors, meningiomas are the majority of them [2, 6, 7, 12, 13, 1921, 28], but no cases of syringobulbia associated with meningioma has been reported (Table 1). There are three distinct groups of cavities in the spinal cord [16, 17]. The hydromyelic or communicating form that is centrally located within the cord and opens rostrally into the fourth ventricle. The second form is the syringomyelic or noncommunicating, where the rostral end of the cavity is closed below its opening into the fourth ventricle [25]. The third form, named as extracanalicular syrinx, is secondary to a spinal cord injury [2]. The large majority of modern investigators believe that the pathogenesis of syringomyelia associated with a lesion in the Fig. 2 Postoperative brain MRI in axial (a) and sagittal (b) T1weighted images showed the complete removal of the tumor; the postoperative cervico-dorsal MRI in sagittal T2-weighted image showed, after 6 months, the complete resolution of the syrinobulbia (c) PCF is related to a disturbance in the circulation of the cerebrospinal fluid (CSF). Gardner [14] proposed that a congenital defect in the fourth ventricle would cause abnormal pulsations of the CSF directed into the central canal, causing hydromyelia. Williams [3033] postulated that an obstruction of the subarachnoid space at the foramen magnum could act as a valve, allowing CSF to cross the foramen magnum rostrally more effectively than caudally. Activities, such as coughing, could cause prolonged elevation of intracranial CSF pressure relative to intraspinal CSF pressure. During this period of craniospinal dissociation, CSF may be sucked from the fourth ventricle into the central canal [22]. A major problem with these hydrodynamical theories is the claim that the source of syrinx fluid is CSF entering the central canal from the fourth ventricle. Detailed neuropathological investigations [16, 25] have shown that communication of the syrinx with the fourth ventricle occurs only in the hydromyelic form. As a result, several theories have been proposed, all of which assert that the source of syrinx fluid in the noncommunicating form of syringomyelia is the CSF in the spinal subarachnoid space [22]. Ball and Dayan [4] emphasized the importance of activities that increase thoracic or abdominal pressure. These increase epidural venous pressure and spinal CSF pressure. The spinal Syringobulbia Surgery NA NA Table 1 Review of the literature of PCF meningiomas with syringomyelia Age/ Dimension Tumor Syrinx Duration MR-syrinx/ sex (cm) sympt. sympt. of sympt. hydrocephalus + NA + + + + NA + NA information not available, VP ventriculoperitoneal, Sympt symptoms, RC retromastoid craniectomy a Extent of syrinx not reported CSF, instead of entering the intracranial subarachnoid space, cannot cross the foramen magnum because of the obstruction; so, it is diverted into the spinal cord parenchyma along Virchow-Robin spaces [22]. Aboulker [1] proposed that obstruction at the foramen magnum interferes with intracranial drainage of the CSF produced in the spinal cord and nerve roots. Heiss et al., Levy et al., and Oldfield et al. [15, 23, 26] proposed that the force impelling spinal su (...truncated)