|Year : 2015 | Volume
| Issue : 5 | Page : 630-632
Intracranial neurenteric cyst traversing the brainstem
Jasmit Singh, Hrushikesh Kharosekar, Vernon Velho, Pravin Survashe
Department of Neurosurgery, Grant Medical College and Sir J J Group of Hospitals, Mumbai, Maharashtra, India
|Date of Web Publication||10-Sep-2015|
Department of Neurosurgery, Grant Medical College and J J Group of Hospitals, Byculla, Mumbai - 400 008, Maharashtra
Source of Support: Nil., Conflict of Interest: None declared.
Neurenteric cysts (NECs), also called enterogenous cysts, are rare benign endodermal lesions of the central nervous system that probably result from separation failure of the notochord and upper gastrointestinal tract. Most frequently they are found in the lower cervical spine or the upper thoracic spine. Intracranial occurrence is rare and mostly confined to infratentorial compartment, in prepontine region [51%]. Other common locations are fourth ventricle and cerebellopontine angle. There are few reports of NEC in medulla or the cerebellum. Because of the rarity of the disease and common radiological findings, they are misinterpreted as arachnoid or simple cysts until the histopathological confirmation, unless suspected preoperatively. We herein report a rare yet interesting case of intracranial NEC traversing across the brainstem.
Keywords: Brainstem, neurenteric cyst, suprafacial triangle, transvermian
|How to cite this article:|
Singh J, Kharosekar H, Velho V, Survashe P. Intracranial neurenteric cyst traversing the brainstem. Med J DY Patil Univ 2015;8:630-2
| Introduction|| |
Neurenteric cysts (NECs), also called enterogenous cysts, are rare benign endodermal lesions of the central nervous system (CNS) that probably result from separation failure of the notochord and upper gastrointestinal tract. Most frequently they are found in the lower cervical spine or the upper thoracic spine. Intracranial occurrence is rare and mostly confined to infratentorial compartment, in prepontine region [51%]. Other common locations are fourth ventricle and cerebellopontine angle. There are few reports of NEC in medulla or the cerebellum. Because of the rarity of the disease and common radiological findings, they are misinterpreted as arachnoid or simple cysts until the histopathological confirmation, unless suspected preoperatively. We herein report a rare yet interesting case of intracranial NEC traversing across the brainstem.
| Case Report|| |
A 33-year-old female presented to us with history of generalized headache from past 2 years, which was persistent and progressive. Patient also had complaints double vision, imbalance while walking, facial deviation to right and nasal regurgitation of food. Neurological examination demonstrated normal mentation; cranial nerve examination revealed bilateral pendular nystagmus and left VIth through Xth nerve involvement; facial paresis was lower motor neuron type grade 2. Patient also had cerebellar ataxia on left side. Computed tomography (CT) brain and magnetic resonance imaging (MRI) brain with contrast revealed a lobulated heterogeneous mass with predominant cystic component in lower pons and medulla with compression of IVth ventricle [Figure 1]. A provisional diagnosis of pontine glioma was made. Patient underwent midline sub occipital craniotomy, drainage of the cyst and decompression of the lesion via transvermian approach (as patient had ataxia). The incision was made in suprafacial triangle and floor of fourth ventricle was opened. The cyst was identified as milky white walled structure. The cystic component consisted of thick collection which was mucoid; the cyst was extra-axial and adherent to brainstem, extending ventrally into the prepontine space. The cyst was marsupialized and biopsy from the wall of the cyst was obtained. Patient was gradually weaned off ventilator and was extubated. Patient remained neurologically preserved barring mild worsening of ataxia. The fluid was reported as sterile and Histopathology was suggestive of NEC. Course following surgery was uneventful. Patient was discharged in satisfactory condition and is following with us regularly [Figure 2].
|Figure 1: Preoperative magnetic resonance imaging brain T1 weighted images showing heterogenous lesion in lower pons and medulla|
Click here to view
|Figure 2: Postoperative computed tomography brain with contrast and histopathological image|
Click here to view
| Discussion|| |
Neurenteric cyst, also known as enterogenous, endodermal, respiratory or bronchogenic cyst is rare congenital lesion of CNS that is mostly found in extramedullary intradural space in lower cervical and upper thoracic spine. Intracranial is even rarer, with majority in posterior fossa. The exact pathogenesis remains unknown; intracranial NEC is thought to arise from a failure of dissolution of transient neurenteric canal between foregut or respiratory buds and the notochord. Early in embryonic development the primary mesoderm that gives rise to notochord, comes to lie in close contact with endoderm, a process called intercalation. At a later stage, when separation occurs group of endodermal cells may be carried back with the mesoderm to give rise to enterogenous cyst.,
In 1934, Puusepp reported first case of NEC in a 27-year-old woman with quadriparesis. NEC can present at a wide range of ages from newborn to the fifth decade of life. They are 2-3 times more common in males. The Intraspinal NEC account for 0.3-0.5% of IDEM lesions and are 3 times more common than the intracranial counterpart., Intracranial NEC is the most common in posterior fossa, of which intradural space anterior to brainstem is the most frequent location.
Neurenteric cyst can cause symptoms by an inflammatory reaction or by mass effect. Active secretion by Goblet cells lining the epithelium can result in expansion of the cyst thereby compressing neighboring neurovascular structures; therefore clinical presentation depends upon location of the cyst. Neurological deficits in order of frequency include motor weakness, sensory loss and sphincter disturbance in case of intraspinal NEC; and in intracranial NEC most frequent complaint is headache followed by gait disturbance, motor, cranial nerve, and sensory disturbance. Intermittent leakage of cyst contents can result in recurrent aseptic meningitis.
Neurenteric cyst is seldom thought as a differential diagnosis on the basis of clinical profile alone. The radiological characteristics of NEC are quite variable. This is attributed to the presence of proteinaceous or other hydrophilic contents. CT scanning usually reveals a hypodense lesion, but some cases may be missed. Considering the dynamic range of sequences and resolution, MRI is the diagnostic modality of choice. The NEC may appear hypointense, isointense or occasionally hyperintense on T1 weighted image; and hyperintense on T2 weighted image and fluid attenuation inversion recovery sequence. The cyst wall does not usually enhance with contrast. The treatment for symptomatic NEC is purely surgical. Because of benign nature of the disease the goal of surgery should be complete excision provided the dissection can be performed without damaging neighboring vital structures. If the cyst wall is adherent to brainstem or vasculature, subtotal resection is a reasonable alternative. Intraoperative NEC appears as yellow or milky white lesions filled with gelatinous or mucoid fluid. Since the clinical and radiological picture is not diagnostic, the diagnosis is evident only after histopathological confirmation. Histologically, they are benign lesions characterized by a cyst wall lined with simple or pseudostratified cuboidal to columnar epithelium with a basement membrane resembling those of respiratory or intestinal tract.,
In the case presented here in, NEC was not thought of as primary diagnosis. Intraoperatively, there was evidence of milky white fluid from the cyst; the cyst was seen traversing the brainstem into the prepontine space. The histopathology confirmed the diagnosis in our case. As the cyst was adherent to the brainstem complete excision was not done; therefore strict surveillance has been advised.
| Conclusion|| |
This interesting case reminds us that NEC should be thought of as a differential diagnosis in cases of brainstem lesions that are predominantly cystic.
| References|| |
Liu JK, Couldwell WT. Far-lateral transcondylar approach: Surgical technique and its application in neurenteric cysts of the cervicomedullary junction. Report of two cases. Neurosurg Focus 2005;19:E9.
Lee CW, Lee SH, Yu ST. Intracranial neuroenteric cyst of the anterior brainstem in a girl. J Korean Child Neurol Soc 2012;20:18-22.
Priamo FA, Jimenez ED, Benardete EA. Posterior fossa neurenteric cysts can expand rapidly: Case report. Skull Base Rep 2011;1:115-24.
[Figure 1], [Figure 2]