Hypoglossal nerve schwannoma: a case report in a pediatric patient

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Abstract

Case Presentation: An 8-year-old previously healthy male patient sought medical attention for a four-month history of gait disturbance, associated with dysarthria and headache with progressive worsening. Upon examination, a MRI identified a heterogeneous mass with cystic components and magnetic susceptibility artifacts in between, suggestive of hemoglobin degradation/calcifications, measuring approximately 5.6 x 4.0 x 4.5 cm in the right ponto-cerebellar cistern. The mentioned expansive lesion determines extrinsic compressive effect on the right cerebellar hemisphere and brainstem, with obliteration of the IV ventricle, reduction of the amplitude of the mesencephalic aqueduct, contact with the sigmoid sinus laterally, and cranial displacement of the right trigeminal nerve. Surgery: A right-sided retrosigmoid craniotomy was performed, with gross total resection, and two anchoring points were visualized next to the right cerebellar hemisphere. Postoperative: The patient had a good postoperative outcome, except for persistent dysphagia, which led the medical team to contraindicate oral intake. Diagnosis: Histopathological examination classified the tumor fragments as astrocytomas, however, immunohistochemistry showed that it was actually a Ki 67 1% schwannoma, indicating that the tumor is benign and has a low cellular growth rate, which is a good prognosis for the patient.

Discussion: Schwannoma of the Hypoglossal nerve is a benign tumor developed from the Schwann cells that involve that nerve. This type of tumor accounts for only 5% of non-vestibular schwannomas. In addition, this disease rarely occurs in pediatric patients, turning the described case relevant to the scientific community. Common symptoms include dysphagia, hoarseness, cervical pain and tongue paresis. These symptoms may vary depending on the location of the tumor - usually intracranial. With slow growth, the schwannomas usually cause clinical manifestations when they are approximately 2 cm in diameter. Complete surgical resection is the treatment of choice, but it can be hard because of the important neurovascular structures that surround it. In pediatric patients, prognosis is usually favorable.

Final Comments: The report presents a rare case of hypoglossal schwannoma, with an unusual patient age and tumor characteristic, which may be useful for the medical community dealing with similar cases.

Publication History

Article published online:
12 May 2025