Introduction
Schwannoma is a benign, encapsulated peripheral nerve sheath tumor arising from Schwann cells, most commonly presenting as a solitary, slow-growing lesion (1,2). Although these tumors may occur anywhere along cranial, peripheral, or autonomic nerves, extracranial schwannomas of the head and neck account for approximately one-quarter to almost half of all cases, with only a small proportion originating from the cervical vagus nerve (1,3). Vagal schwannomas typically affect adults in the third to fifth decades of life and are generally benign; although malignant transformation is rare, it has been documented (4).
Despite their benign nature, schwannomas in the cervical region pose a diagnostic challenge due to their rarity and their tendency to mimic several parapharyngeal or lateral neck masses (3). Their deep anatomic location limits early detection and renders pre-operative suspicion difficult, particularly as patients may remain asymptomatic for prolonged periods of time (1). This diagnostic ambiguity contributes to delayed identification and misclassification.
Failure to recognize cervical vagal schwannoma (CVS) can complicate clinical decision-making, may contribute to inappropriate differential diagnoses and hinder optimal treatment planning. Moreover, although typically indolent, these tumors may progressively become enlarged, causing functional impairment or displacement of adjacent neurovascular structures (4). Misinterpretation may also result in unnecessary or inappropriate interventions.
Various strategies exist for the evaluation and management of schwannomas; however, their application relies heavily on correct preoperative identification. The rarity of CVS limits clinician familiarity with its epidemiological behavior and typical presentation. Furthermore, available reports highlight that a number of cases continue to be diagnosed only after surgical excision (3).
The case presented herein is uncommon due to the young age of the patient, the imaging features that closely mimicked a paraganglioma leading to an initial misdiagnosis, and the successful nerve-preserving excision with an uncomplicated postoperative course.
Discussion
CVS is a rare benign peripheral nerve sheath tumor derived from Schwann cells and represents one of the least common neurogenic masses in the neck (3,5). Although head and neck schwannomas account for ~25-45% of all extracranial schwannoma cases, only a small proportion originate from the vagus nerve, rendering diagnosis particularly challenging. The clinical significance of these cases lies in their variable presentations, frequent potential for misdiagnosis and the implications for preserving nerve function during surgical intervention. These tumors most commonly occur in adults between the third and fifth decades of life, with no clear sex predilection (6,7).
In order to better contextualize the present case, the authors reviewed previously reported cases of CVS focusing on clinical presentation, imaging features, management strategies and outcomes. A total of eight reported cases of cervical vagal nerve schwannoma were identified as representative samples in the literature, with the ages of the patients ranging from 13 to 42 years. Tumor sizes varied considerably, from 4 to 13 cm, and the majority of lesions arose from the right cervical vagus nerve, with only one case involving the left side. The diagnostic evaluation most commonly included an ultrasonography, computed tomography scan, fine needle aspiration cytology and MRI, whereas some reports additionally used digital subtraction angiography (DSA) or intraoperative transcranial motor-evoked potential (TcMEP) monitoring. Surgical management in all cases involved tumor excision, performed as intracapsular or subcapsular enucleation, or as total resection, with nerve preservation achieved in the majority of procedures. Post-operative outcomes were generally favorable; several patients demonstrated complete recovery or clinical improvement, no recurrence and was reported during follow-up of up to 5 years, although some cases experienced complications, such as hoarseness, dysphonia, laryngeal paralysis or persistent facial pain. Overall, surgical excision remains the primary therapeutic modality, with the majority of patients maintaining satisfactory postoperative function and recovery (1,4,8-13) (Table III).
Typically, slow-growing and asymptomatic, vagal schwannomas may be mistaken for other parapharyngeal or carotid space lesions, such as paragangliomas, lymphadenopathy, neurofibromas, or salivary gland tumors due to overlapping clinical and radiological features (6,14,15). An MRI plays a central role in the evaluation process; however, differentiating schwannomas from paragangliomas remains difficult due to shared radiographic characteristics, including carotid bifurcation splaying and heterogeneous T2 signal intensity. Therefore, a definitive diagnosis often relies on a histopathological confirmation (16). In the case described herein, a 26-year-old patient presented with a newly developed left cervical mass following a flu-like illness. Although the temporal association suggested a possible inflammatory process, the clinical behavior and radiological appearance of the lesion indicated a neoplastic process. The mass was non-tender, mobile laterally and located between major vascular structures, which are features consistent with vagal schwannoma (3).
An ultrasonography and MRI demonstrated carotid bifurcation splaying and internal vascularity, initially leading to a radiological impression of paraganglioma. This finding is consistent with the observations reported in the study by Tzortzis et al (16), who noted that vagal schwannomas can mimic carotid body tumors or sympathetic chain schwannomas due to similar vascular displacement patterns. As with several other cases, the schwannoma in the patient described in the present case report remained radiologically indistinguishable from a paraganglioma until definitive histopathological confirmation was obtained.
Although the majority of reported cases describe progressive symptoms, such as hoarseness, dysphagia, or paroxysmal cough triggered by palpation a sign often considered pathognomonic, the patient in the present case report was entirely asymptomatic, apart from localized swelling. This clinical course is consistent with previously reported cases of asymptomatic or incidentally discovered cervical vagal schwannomas, in which patients present with minimal or no neurological symptoms despite the tumor's close proximity to vital neurovascular structures (3,7,14,16).
Surgical excision remains the definitive treatment for CVS, as is consistently supported in the literature (3,16). While earlier studies have suggested that nerve preservation is challenging due to fascicular involvement (17), recent evidence suggests that extracapsular dissection or enucleation are effective methods for the preservation of nerve integrity and minimizing post-operative morbidity (16). In the case presented herein, complete tumor excision was achieved with preservation of the vagus nerve and without post-operative complications, consistent with the favorable outcomes reported in more recent surgical series (16,18).
However, as demonstrated by Tanaka et al (13), vagal dysfunction may still occur post-operatively due to traction or ischemia during surgery, even when anatomical preservation appears to be achieved. The absence of neurological impairment in the patient in the present case report highlights the importance of meticulous microsurgical technique, particularly in smaller tumors where the risk may be lower. The present case report further underscores the ongoing diagnostic ambiguity associated with vagal schwannomas. The initial misclassification as a paraganglioma illustrates the limitations of radiological assessment and emphasizes the importance of histopathological confirmation. Moreover, the lack of pre-operative neurological symptoms and the uncomplicated postoperative course suggest that early detection and smaller tumor size may contribute to more favorable outcomes.
Complete recovery without vocal cord dysfunction or wound-related complications is in contrast to the findings of other published cases reporting post-operative hoarseness or vocal fold palsy (3,18). This difference may reflect variations in tumor size, the extent of nerve involvement and surgical expertise.
The present case report has several key limitations that should be mentioned. First, germline genetic testing for schwannomatosis-associated genes (NF2, SMARCB1 and LZTR1) was not performed. Given the young age of the patient, such testing would have been valuable to exclude an underlying hereditary tumor predisposition syndrome and to inform long-term surveillance strategies. However, comprehensive germline genetic testing is not locally available in Iraq and requires referral to international laboratories, which limits accessibility in the authors' setting.
Second, tumor molecular analysis for 22q11 deletion and somatic NF2 mutations was not conducted. These alterations are frequently reported in sporadic schwannomas and may provide insight into tumor pathogenesis and recurrence risk. Nevertheless, the authors' institution (Tikrit Teaching Hospital, Tikrit, Iraq) lacks the necessary molecular pathology infrastructure, including fluorescence in situ hybridization, chromosomal microarray analysis, and next-generation sequencing, and international referral poses additional logistical challenges. Ultrasound images were unavailable for inclusion in this report because image archiving is not fully integrated between the hospital information system and the ultrasound unit at the authors' institution.
Third, comprehensive brain and spine MRI screening for additional schwannomas was not performed. This decision was based on the isolated nature of the lesion, the absence of syndromic features, a negative family history, and a normal neurological examination. While such screening is recommended in patients with confirmed hereditary syndromes, it is not routinely indicated for solitary sporadic schwannomas. The patient remains under clinical surveillance with ongoing neurological follow-up.
In conclusion, CVS is a rare diagnostic challenge that often mimics other carotid-space lesions. Definitive diagnosis and nerve-preserving excision can result in an uncomplicated recovery with full functional preservation.