Fifth ventricle: an unusual cystic lesion of the conus medullaris

Abstract

Study design: Cystic dilatation of the fifth ventricle on its own is an extremely rare pathological event in adults whose pathogenesis is uncertain. The authors describe a personal case of 'fifth ventricle' and review the pertinent literature. Objective: To emphasize the importance of including the fifth ventricle in differential diagnosis of lesions of the conus medullaris to ensure proper treatment. Setting: Italy. Methods: A 30-year-old woman was referred to us for recurrent low back pain. The patient was assessed by clinical, electrophysiological (motor evoked potential, somatosensorial evoked potential and electromyography of the perineal and lower limb muscles) and urodynamic investigations as well as a magnetic resonance imaging (MRI) of the lumbar-sacral segment with and without gadolinium enhancement, subsequently extended to the entire vertebral column and brain. Follow-up consisted of periodic clinical evaluation and lumbar-sacral MRI after 1 and 2 years. Results: General physical examination, electrophysiological and urodynamic investigations were all negative, confirming the subjective nature of the patient's symptoms. Lumbar-sacral MRI demonstrated the presence of a cyst lesion containing cerebrospinal fluid (CSF), which did not enhance after gadolinium, compatible with the diagnosis of the terminal ventricle. By extending the MRI investigation to the entire vertebral column and brain, it was possible to exclude an association with other malformations of the central nervous system. Clinical and radiological follow-up confirmed the nonevolutive nature of the lesion 1 and 2 years later. Conclusions: The lack of clinical symptoms and the stability of the radiological situation at 1 and 2 years follow-up motivated our choice of conservative treatment.Spinal Cord (2005) 43, 381-384.

Intramedullary arachnoid cyst: Report of two cases

“…The characteristic MRI findings of an intramedullary arachnoid cyst include a cystic lesion of CSF intensity, hypointense to the normal cord tissue in T1-weighted images and hyperintense on T2-weighted images with no contrast uptake and no perilesional edema. Important differential diagnosis of a cystic conus lesion includes a terminal (fifth) ventricle, [12] focal syringomyelia, epidermoid, and ependymoma. However, it is often not possible to differentiate radiologically between an arachnoid cyst, focal syrinx, and terminal ventricle.…”

Microsurgical fenestration of idiopathic intramedullary cysts in adult patients

“…Another noteworthy aspect of our series is the fact that all enrolled patients are female. This apparent predominance of female patients suffering from intramedullary cysts has also been described previously and might indicate a gender-related predisposition [2,[8][9][10][11][12]. This influence of gender is nothing unusual in spinal developmental conditions such as neural tube defects [24].…”

“…As for pain syndromes, one possible explanation might be a better recovery potential of nociceptive neurons against metabolic derangement caused by mechanic stress, comparable to the situation in patients with tethered cord syndrome, as proposed by Yamada et al [23]. The good response of associated pain syndromes, especially sciatica to surgery has also been described by other authors [9]. In our series, we found patients with local as well as neuropathic pain syndromes to benefit from surgery, which might be explained by the absence of secondary degenerative spinal pathologies (i.e., spinal stenosis, spondylosis).…”

“…Due to the lack of larger studies, the optimal course of treatment remains debatable with some authors preferring a conservative approach, especially in oligo-or asymptomatic cases, and others advocating invasive treatment [2,5,8,9,15]. Available options consist of decompressive surgery via fenestration or cyst wall resection as recommended by others [1,4,5,8,11,12,15,16].…”

“…In this location, cysts constitute dilations of the central canal and are also referred to as ''fifth ventricle'' or ''terminal ventricle'' [1][2][3][4][5][6][7][8][9][10][11][12]. Only very few cases have been published, and the exact incidence rate of these lesions in adult patients still remains uncertain.…”