Background

Neuroblastic tumors arise from primitive sympathetic ganglion cells and are the most common extracranial solid tumor of childhood [1]. There are three recognized types—neuroblastomas, ganglioneuroblastoma, and ganglioneuromas. These tumors vary in their proportions of Schwann cells and neuroblasts. Classification is based on histological features including the degree of differentiation and cellular maturation. Neuroblastomas are aggressive and poorly differentiated, with decreased Schwann cells in the stroma. Ganglioneuroblastomas vary in the degree of Schwann cells but generally include an intermixed picture of Schwann cells and neuroblasts. The subtype, ganglioneuroma, is the most well-differentiated, with a dominant presence of Schwann cells in the stroma [1, 2]. This subtype is the most benign and comprises less than 1% of all soft tissue tumors. It most commonly occurs in the adrenal medulla, extra-adrenal retroperitoneum, and posterior mediastinum. One to 5% of these extremely uncommon tumors occur in the head and neck, with the parapharyngeal space (PPS) being a potential subsite [3, 4].

The PPS is a triangular compartment lateral to the upper pharynx composed primarily of fat, with the apex of the triangle at the hyoid and the base at the skull. Given its deep location, most PPS masses are not detectable on physical examination [5, 6]. Furthermore, while parapharyngeal masses are most commonly neoplastic in adults, these masses tend to have infectious causes in children [7]. It is quite uncommon to find a physically detectable, neoplastic parapharyngeal mass in a pediatric patient. We present the case of a 7-year-old boy with a large ganglioneuroma of the PPS and provide an updated review of the literature on the presentation of ganglioneuromas.

Case presentation

We report a 7-year-old boy with a history of recurrent otitis media who presented with 2 months of cervical lymphadenopathy. There has been no family history of this presenting condition. Ultrasound suggested reactive lymphadenopathy. Lymphadenopathy persisted after 10 days of clindamycin; thus, a CT was obtained. This revealed a 2.6 × 2.7 × 6.1 cm mass in the left PPS extending from the mandible to the thyroid, with a displacement of the internal jugular vein and common carotid artery (Figs. 1 and 2). A specimen obtained via fine-needle aspiration stained positive for S100 with negative SMA in the spindle cells, supporting the diagnosis of ganglioneuroma. MRI was performed for further characterization (Figs. 3 and 4). There were no diagnostic challenges to be reported. The patient began to experience neck pain and odynophagia; thus, we proceeded with surgical excision.

Fig. 1
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CT axial view

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Fig. 2
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CT coronal view

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Fig. 3
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MRI T2 axial view

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Fig. 4
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MRI T2 coronal view

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Complete excision of the tumor was performed via neck dissection. The tumor was beneath the vagus nerve, which was skeletonized, preserved, and remained intact on intraoperative nerve stimulation. The carotid artery and internal jugular vein were preserved along with their branches. The tumor was noted to be attached to cervical nerve rootlets. The nerve rootlets of cranial nerves XI and XII and phrenic nerves were stimulated and noted to be intact, which established that the tumor was not related to these nerve roots.

Postoperatively, the patient developed a mild left Horner’s syndrome (HS). All other cranial nerves were intact. The final pathology confirmed the mass to be a ganglioneuroma. The patient’s postoperative HS without other neuropathies suggests the mass to be a ganglioneuroma of the cervical sympathetic chain.

Discussion

Ganglioneuromas are benign, non-invasive tumors of the neural crest cells that give rise to the sympathetic nervous system. These tumors most commonly occur in the trunk; however, 1–5% occur in the head and neck [4]. Cervical ganglioneuromas commonly present as slow-growing masses that cause compressive symptoms or as incidental findings on imaging. It has been reported that these tumors can cause symptoms related to catecholamine release; however, this was not present in our case nor in any reviewed cases of the last 15 years. Patients most commonly present in childhood or early adulthood, with management usually consisting of regular monitoring. Surgical resection is reserved for symptomatic patients. Recurrence is rare, with one incidence recorded in the literature. Resection is commonly complicated by self-limited postoperative HS due to disruption of the sympathetic cervical chain [8,9,10,11,12,13,14,15].

Here, we present a 7-year-old male with an initially asymptomatic neck mass that subsequently became associated with neck pain and odynophagia. The patient was found to have a parapharyngeal ganglioneuroma that was surgically excised, with the only complication being mild ipsilateral HS. This presentation and treatment outcome is consistent with other sympathetic chain parapharyngeal ganglioneuromas presented in the literature [8,9,10,11,12,13, 15]. This presentation is not universal, however varying based on the location of the lesion and the age of the patient.

In our review of the literature, there are 23 reported cases of ganglioneuroma affecting the head and neck. Sixteen of 23 occurred in patients under the age of 30 with a median age of 17, consistent with reported distributions of incidence [14]. Of the 16 cases in patients under 30, 9 presented with a chief complaint of a neck mass, making it the most common presentation in that group (Table 1). Most of these presented in the absence of other symptoms. There were no cases of patients over 20 years of age presenting with a discernible neck mass [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30]. Of the 23 reported cases reviewed, 7 presented with postoperative Horner’s syndrome (about 30%). Of those, 4/7 cases of postoperative Horner’s syndrome resolved [8,9,10,11,12,13, 15].

Table 1 Prevalence of presenting symptoms in the reviewed literature
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Interestingly, patients with ganglioneuromas in the para- or retropharyngeal spaces more commonly presented with an identifiable neck mass. In our review, 8 patients were found to have para- or retropharyngeal masses, with 5 of the 8 initially presenting with a neck mass. Two of the other patients presented with symptoms of compression: cough, neck pain, and stiffness. The third was discovered incidentally on imaging. The second most common subsite was prevertebral and cervical spine with 6 cases, with other reported cases in the submandibular space, external and internal auditory canals, uveal tract, base of the tongue, superior orbit, inferior jugular region, and the glossopharyngeal tract [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30].

Conclusions

Our case illustrates a key example of neurogenic tumor presentation, with a pediatric patient presenting with an initially asymptomatic neck mass that ultimately caused compressive symptoms, all in the absence of systemic signs or tissue invasion. Ganglioneuroma is an important consideration in the diagnosis of a neck mass in a child, especially after more common etiologies, including infection, lymphoma, and benign congenital masses, have been considered. Children with a ganglioneuroma may commonly present with no signs of compression or systemic signs but still must continue to be monitored for symptomatic transformation with continued growth and advised on the risks and benefits of excision.