Heterotopic neuroglial mass in the parapharyngeal space causing dysphagia in a 4 years old child: A case report

Abstract

Introduction

Neuroglial heterotopia represents a rare differential diagnosis for pediatric neck masses. Its occurrence in the parapharyngeal space is exceptionally uncommon, with fewer than 30 documented cases in the literature.

Case report

This report details the case of a 4-year-old girl initially noted to have a mass in the right parotid area at birth with no symptoms. After observation, she returned at the age of 4 with dysphagia and a visible mass in the same area. Subsequent CT imaging revealed a mass in the right parapharyngeal space, prompting surgical intervention. Histological examination after resection confirmed the diagnosis of neuroglial heterotopia.

Discussion

Neuroglial heterotopia manifests with various symptoms in pediatric patients, posing diagnostic challenges due to the lack of specific radiological or clinical features distinguishing it from other neck masses in children.

Conclusion

This case highlights the significance of considering neuroglial heterotopia in pediatric neck region masses diagnoses. Further research is needed to better understand its clinical features and treatment options.

Highlights

• •Parapharyngeal Heterotopic glial tissue is rarely diagnosed in pediatric patients.
• •Most neuroglial tissue malposition occurs in the nasal cavity.
• •There is a higher tendency towards diagnosing neurological heterotopia in childhood.
• •The most commonly approved treatment for symptomatic cases is surgery.
• •High specificity diagnostic testing before surgery is still lacking.

1. Introduction

Neuroglial heterotopia is a rare congenital benign lesion characterized by the presence of ectopic neuroglial cells outside of the central nervous system CNS [1,2]. While it most commonly occurs in the nasal cavity, it can also manifest in the neck, palate, orbit, and other regions [2,3]. Its occurrence in the parapharyngeal space is exceedingly rare [4]. Symptoms of neuroglial heterotopia typically present in infancy with manifestations, such as airway obstruction, poor feeding, snoring, and dysphagia [1,3,4].

The exact etiology of neuroglial heterotopia remains unclear, and several theories have been proposed to explain its pathogenesis. The widely accepted encephalocele theory suggests that heterotopic neuroglial tissue may arise from encephaloceles that lose their intracranial connection. Other theories include the development of mature neural tissue from displaced totipotent ectodermal cells or the migration of abnormal glial cells from the olfactory bulb [4]. Notably, neuroglial heterotopia cases may also coexist with other congenital anomalies such as heart defects, Pierre Robin sequence, and cleft palates [1,3,5]. Diagnostic challenges arise due to the lack of specific medical or radiological features distinguishing it from other masses. Common differentials include vascular anomalies, teratomas, deep neck space infections, nerve sheath tumors, lymphomas, and other malignancies [4]. In our presented case, initial clinical and imaging assessments suggested a diagnosis of lymphatic malformation (cystic hygroma), prompting surgical intervention due to symptomatic presentation. We depended upon the SCARE criteria to reach the final version of this case report [6].

2. Presentation of case

The patient, a four-year-old female infant, was brought to our attention due to complaints of dysphagia along with the presence of a visible mass in the right parotid area.

At birth, the infant was noted to have a palpable mass on the right side of her neck, especially over the parotid gland area, although there were no associated respiratory or swallowing difficulties reported then. Perinatal imaging was indicated to determine the mass characteristics and its mostly associated pathology. Magnetic Resonance Imaging (MRI) was done, which revealed a cystic mass located within the right parapharyngeal space. The initial radiological interpretation (MRI at birth) leaned towards a diagnosis of lymphatic malformation (cystic hygroma), considering the typical differential diagnoses for masses in this age group, including congenital anomalies such as vascular malformations and teratomas, as well as inflammatory conditions like deep neck space infections, nerve sheath tumors, lymphomas, and other neoplasms. As though the medical recommendation was to stay on a conservative treatment plan with continual observation, follow up of the mass development, and detecting newly presence of any related symptoms.

As the child reached four years of age, she remained largely asymptomatic for pain or respiratory distress. However, diagnostic imaging with Computed Tomography (CT) unveiled a substantial cystic mass positioned deep under the right parotid gland, extending into the parapharyngeal space (Fig. 1). This anatomical extension corresponded well with the recent onset of dysphagia symptoms. Notably, the CT scan also indicated regional enlargement of the right mandibular bone, suggestive of bony distraction, a feature occasionally associated with such masses.

Fig. 1.

CT-coronal, sagittal, and transverse sections showing a large mass in the right parapharyngyeal space and the regional deformity of the right mandibular bone.

Following comprehensive multidisciplinary discussions involving pediatric otolaryngologists, radiologists, and pediatric surgeons, a consensus was reached to proceed with surgical exploration and excision due to the symptomatic nature of the mass and the diagnostic ambiguity based solely on imaging studies. Coming from a low-income country, perioperative challenges included making sure to have the adequate and appropriate equipments and the reliable supply of oxygen and blood products. Since pediatric patients have different anatomical features and behave differently and unpredictably than adult patients, having a smooth and calm approach during surgery is considered essential. It was also important to have a well-planned dosing and a tailored anesthetic approach to avoid any critical anesthesia-related incidents.

During the surgical procedure performed under general anesthesia, we ensured the optimal preservation of facial nerve function. A combined transparotid–transcervical approach was meticulously executed to expose and access the mass. Surgical steps included careful removal of the submandibular gland, precise transection of the styloid ligament, and meticulous dissection of anatomical structures such as the Sternocleidomastoid muscle, digastric muscle, external carotid artery, and carotid sheath to gain appropriate exposure to the mass.

The mass located deeply to the parotid gland and exerting compressive forces on adjacent structures including the internal carotid artery, pushing it posteriorly and laterally (Fig. 2). Special attention was paid to preserving the Marginal mandibular branch of the facial nerve during this dissection. Superiorly, the mass extended to the skull base, displaying adherence to the adjacent pterygoid plates of the sphenoid bone. Careful and methodical dissection techniques were employed to release the mass from its parapharyngeal location to the pterygoid palate and the base of the skull. A small residual root adhering posteriorly was identified and separated from the internal carotid artery, and local Bleomycin injection was applied as an adjunctive measure before completing the excision (Fig. 3).

Fig. 2.

The mass, located deeply to the parotid gland, pushing the internal carotid artery posteriorly and laterally.

Fig. 3.

The mass was carefully dissected off the facial nerve, carotid artery, and jugular vein. The safety of all structures was confirmed.

Post-surgical histopathological examination of the excised tissue revealed an infiltrative pattern of fibrillar tissue positive for Glial Fibrillary Acidic Protein (GFAP), with rare identified neurons. Notably, no atypical cells or significant mitotic activity were observed, consistent with a diagnosis of heterotopic neuroglial tissue. This histological confirmation provided valuable insights into the nature of the mass and affirmed the appropriateness of the surgical intervention, without future relapses in the associated anatomical region after one year of follow-up and observation of the patient.

3. Discussion

Neuroglial heterotopia represents a rare and intriguing entity, especially when found in the parapharyngeal space, as only fewer than 30 cases have been reported in the medical literature [5]. Its clinical manifestations can vary widely depending on factors such as the size and location of the mass and its effect on surrounding anatomical structures. A notable feature observed in the literature is its predominant occurrence in infant females, often presenting with left-sided masses [7].

Clinical presentations of neuroglial heterotopia encompass a spectrum of symptoms ranging from respiratory distress [1,11], feeding difficulties and failure to thrive [3,4], to incidental discovery through radiological investigations [5,9]. Some cases even manifest with prenatal or neonatal findings on ultrasound or other imaging modalities [5,7]. Our case aligns with these traits, as the patient initially had a parotid region mass at birth without associated symptoms, later presenting at the age of 4 with dysphagia coinciding with the mass's enlargement extending to the right parapharyngeal space as identified on imaging studies.

Imaging modalities play a pivotal role in diagnosing and characterizing neuroglial heterotopia, with CT and MRI being the mainstay of diagnostic tools in the literature [2,10]. While MRI provides superior soft tissue resolution aiding in lesion characterization, CT excels in delineating bony involvement, such as the observed mandibular distraction in our case, a characteristic often noted in parapharyngeal neuroglial heterotopia cases [5].

The coexistence of neuroglial heterotopia with other congenital anomalies, such as craniofacial abnormalities, underscores the complex developmental origins of this condition [5,8]. However, there are no other congenital anomalies in our described case.

Surgical excision remains the cornerstone of management for neuroglial heterotopia, aiming for complete removal while preserving vital anatomical structures like the facial nerve. However, the optimal timing for surgery remains a subject of debate, balancing the risks of delaying surgery with potential growth-related complications in neonates versus the challenges of surgical planes in this population [4]. Our case highlights successful surgical intervention at age 4, aligning with the practice observed in the literature of surgical excision being the primary treatment modality with few reported recurrences necessitating follow-up surgeries [10,11].

Histological examination remains crucial for definitive diagnosis, as seen in our case where characteristic features of heterotopic neuroglial tissue, including positive staining for GFAP and S100, confirmed the diagnosis. Despite the challenges in clinical and radiological differentiation from other masses, meticulous histopathological analysis remains the gold standard for confirmation.

Overall, while neuroglial heterotopia in the parapharyngeal space presents diagnostic and management challenges, multidisciplinary collaboration, advanced imaging techniques, and histological scrutiny contribute to successful outcomes. Continued research into its etiology, early diagnostic strategies, and long-term follow-up protocols are warranted to further enhance management approaches and mitigate potential complications associated with this rare condition.

4. Conclusion

Neuroglial heterotopia presents a diagnostic challenge due to its varied clinical presentations and lack of specific radiological or clinical features distinguishing it from other pediatric neck masses. Our case report sheds light on this rare condition, emphasizing the importance of considering neuroglial heterotopia in the differential diagnosis of pediatric neck masses, especially in cases presenting with atypical symptoms or complex anatomical involvement.

Collaborative efforts among multidisciplinary teams comprising pediatric otolaryngologists, radiologists, and surgeons are paramount in ensuring accurate diagnosis and timely intervention. Advanced imaging modalities such as CT and MRI play crucial roles in characterizing these lesions.

CRediT authorship contribution statement

Noha Kiki Kharsi: Reviewed the literature, wrote the article's title, abstract and discussion.

Majd Naser: Reviewed the literature, wrote the article's introduction and conclusion.

Alaa Hammad: Reviewed the literature, wrote the detailed case report.

Zein Shaheen: Reviewed the literature, wrote the article's management and outcome.

Areej Alassaf: Oversaw the surgical procedure and managed the scientific and academic aspects of preparing and submitting the manuscript.

All authors reviewed and approved the content of the manuscript.

Consent

An informed consent was obtained from the patient's parents.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Ethical approval

Ethical approval for this study (MD-020624-240) was provided by the Ethical Committee of Damascus University, Faculty of Medicine, Damascus, Syria on 26 June 2024.

Guarantor

Majd Naser.

Declaration of competing interest

None.