Incidentally detected neuroglial cyst in the medulla oblongata

Article information

Neurofunction. 2025;21(1):28-31

Publication date (electronic) : 2025 June 18

doi : https://doi.org/10.52662/nf.2025.00185

Seong-Hyun Park, MD, PhD, Min-Seok Woo, MD, Chaejin Lee, MD, Jeong-Hyun Hwang, MD, PhD

Department of Neurosurgery, Kyungpook National University Hospital, Kyungpook National University School of Medicine, Daegu, Korea

Address for correspondence: Seong-Hyun Park, MD, PhD Department of Neurosurgery, Kyungpook National University Hospital, Kyungpook National University School of Medicine, 130 Dongdeok-ro, Jung-gu, Daegu 41944, Korea Tel: +82-53-200-5652 Fax: +82-53-423-0504 E-mail: nsdoctor@naver.com

Received 2025 May 2; Accepted 2025 June 10.

Abstract

INTRODUCTION

Neuroglial (glioependymal) cysts are rare, benign, congenital lesions of the central nervous system, typically lined by ependymal or glial epithelium. These lesions are thought to arise from embryonic remnants of the primitive neuroectoderm and are most commonly located in the cerebral hemispheres, corpus callosum, or ventricular system [1]. Their occurrence in the brainstem—particularly the medulla oblongata—is exceedingly rare, with only a few cases documented in the literature [2-4].

Clinically, neuroglial cysts are often asymptomatic and detected incidentally. However, in critical regions such as the brainstem, even small lesions may result in neurological deficits due to mass effect on surrounding nuclei or fiber tracts [2,4]. Neuroimaging, particularly magnetic resonance imaging (MRI), plays a crucial role in identifying characteristic features of these cysts, which typically appear as well-circumscribed, non-enhancing, intraaxial cystic lesions without mural nodules or wall thickening [5,6]. Nonetheless, their radiological appearance may overlap with other benign cystic lesions such as neurenteric cysts, ependymal cysts, or arachnoid cysts, necessitating careful differential diagnosis [1,3,6].

Herein, we present a rare case of an incidentally discovered neuroglial cyst located in the medulla oblongata and upper cervical spinal cord, identified during spinal MRI performed for unrelated symptoms. To our knowledge, this represents one of the few reported cases with radiological follow-up over a 1-year period, emphasizing the benign nature and stability of such lesions.

CASE REPORT

A 71-year-old woman underwent spinal MRI for evaluation of chronic lower back pain. Incidentally, a well-defined cystic lesion was identified in the medulla oblongata, prompting referral for further neuroimaging (Fig. 1).

Fig. 1.

Spinal magnetic resonance imaging obtained to evaluate back pain reveals an incidental cystic lesion in the medulla oblongata.

Subsequent brain MRI revealed a 2.7-×1.3-cm intraaxial cystic lesion located centrally in the right paramedian region of the medulla oblongata, with slight extension into the upper cervical spinal cord. The lesion appeared hyperintense on T2-weighted imaging, hypointense on T1-weighted imaging, and demonstrated no enhancement following contrast administration. There were no signs of wall thickening, internal septation, or mural nodules. The lesion’s characteristics were consistent with a benign cystic process, with a neuroglial (glioependymal) cyst considered most likely based on imaging features (Fig. 2).

Fig. 2.

Axial and sagittal brain magnetic resonance imaging sequences: (A) T2-weighted image shows a hyperintense intra-axial cyst in the right paramedian medulla. (B) T1-weighted image shows a corresponding hypointense lesion. (C) Post-contrast T1-weighted image shows no enhancement. (D) Sagittal post-contrast T1-weighted image delineates the lesion extending into the upper cervical spinal cord.

The patient was neurologically intact, and the cyst was not deemed responsible for her presenting symptoms. A conservative approach was adopted, with a plan for serial imaging surveillance.

Follow-up MRI performed 1 year later demonstrated no significant interval change in the size, shape, or signal characteristics of the lesion. The cyst remained stable and asymptomatic, supporting the diagnosis of a benign non-progressive intraaxial cyst. No surgical or medical intervention was pursued.

This study was approved by the Institutional Review Board of Kyungpook National University Hospital (2014-03-013-006). This type of study does not require informed consent.

DISCUSSION

Neuroglial (glioependymal) cysts represent a rare subset of benign, congenital, intraaxial cystic lesions that arise from embryologic remnants of the neuroectoderm. These lesions are typically lined by cuboidal or columnar ependymal or glial epithelium and are most frequently found in supratentorial locations such as the periventricular white matter, corpus callosum, and septum pellucidum [1]. Infratentorial involvement, particularly within the brainstem, is exceedingly rare, and when present, poses unique diagnostic and management considerations due to the critical neuroanatomical structures involved [2,3].

The clinical presentation of neuroglial cysts is highly variable and largely dependent on their size, location, and relationship to adjacent functional structures. While supratentorial cysts are often detected incidentally or associated with symptoms such as headaches, seizures, or hydrocephalus, brainstem lesions may present with more subtle or insidious symptoms owing to the compact and vital architecture of the region [3,4]. However, as exemplified in our case, some cysts—despite their location in eloquent areas such as the medulla oblongata—may remain entirely asymptomatic and stable over time.

In the present case, the cystic lesion was discovered incidentally during spinal MRI performed for the evaluation of chronic lower back pain. The patient was neurologically intact, and there were no complaints suggestive of brainstem involvement. Follow-up MRI performed 1 year later showed no interval change in the lesion’s size, shape, or signal intensity, reinforcing the non-progressive nature of the lesion. This natural history closely parallels that reported by Abdulateef et al. [2], who described a glioependymal cyst in the medulla oblongata that remained stable following decompression. Our case, however, is particularly notable in that the lesion required no intervention at all, further supporting conservative management in asymptomatic cases.

Radiologically, neuroglial cysts typically appear as sharply marginated, intraaxial cystic lesions that are hyperintense on T2-weighted sequences, hypointense on T1-weighted images, and do not enhance following contrast administration. These features help differentiate them from other cystic pathologies such as ependymal cysts, neurenteric cysts, epidermoid cysts, and arachnoid cysts, each of which has distinct imaging characteristics [5,6]. For example, neurenteric cysts may show irregular walls or slight peripheral enhancement [3], while ependymal cysts can be midline and may sometimes be associated with mass effect or distortion of adjacent structures [6]. In our case, the absence of wall thickening, mural nodularity, or enhancement favored a diagnosis of neuroglial cyst.

The importance of radiological pattern recognition in such cases cannot be overstated. As emphasized by Verma et al. [6], a thorough understanding of imaging features can prevent unnecessary surgical exploration or overtreatment. In our patient, the stable radiologic appearance over a 1-year interval, combined with a benign clinical course, made invasive diagnostics or therapeutic intervention unwarranted. This aligns with contemporary approaches that advocate observation in radiologically and clinically stable lesions, particularly in older patients with unrelated comorbidities.

Several authors have reported medullary neuroglial cysts requiring surgical treatment due to progressive neurological deficits [4]. However, cases such as ours and that of Gavrjushin and Chelushkin [3] suggest that a subset of brainstem neuroglial cysts may follow a benign and indolent course, thereby validating non-operative strategies in well-selected patients. The decision to observe rather than operate must be based on a combination of clinical judgment, radiological findings, and patient-specific factors, including age, comorbid conditions, and the absence of neurological compromise.

In summary, this case underscores three key points: (1) the potential for neuroglial cysts to arise in atypical and critical anatomical locations such as the medulla oblongata; (2) the value of MRI in establishing a probable diagnosis and guiding non-invasive management; and (3) the appropriateness of conservative follow-up in asymptomatic, radiologically stable lesions. As more cases are documented and long-term outcomes reported, our understanding of the natural course and optimal management strategies for these rare lesions will continue to evolve.

CONCLUSION

Neuroglial cysts occurring in the medulla oblongata are exceptionally rare and may present as incidental findings in asymptomatic individuals. Despite the eloquent location, such lesions can remain radiologically and clinically stable over time. Accurate recognition of characteristic MRI features—such as intraaxial location, T2 hyperintensity, absence of enhancement, and lack of mass effect—is critical in establishing a presumptive diagnosis and guiding appropriate management.

This case illustrates that a conservative, non-operative approach may be appropriate in select patients, particularly when the lesion is asymptomatic and demonstrates no progression on serial imaging. Careful radiological assessment, long-term monitoring, and avoidance of unnecessary intervention are essential to optimizing outcomes in patients with benign brainstem cystic lesions.

Article information Continued