Vestibular Schwannoma Causing Unilateral Facial Pain in 20-Year-Old Patient

Vestibular schwannoma is the most common cerebellar pontine angle (CPA) tumors that can present with wide range of symptoms like imbalance, facial pain or numbness, hearing loss, headache, and tinnitus. It usually happens between the ages of 30 and 60 years. Here, we are reporting a 20-year-old healthy male who presented to the otolaryngology emergency clinic with unexplained facial pain.

He had 3-weeks history of unilateral right-sided facial pain localized to the ear, mandible, and right half of the tongue, described as electric shock like pain, causing difficulty of eating and swallowing. Clinical neuro-otologic examination with evaluation of the cranial nerves, corneal reflex, hearing test, vestibular function, and fibro-optic examination did not reveal any underlying causes to explain his symptoms. Blood tests were normal. In view of the ambiguity of his symptoms, computed tomography (CT; Figure 1) and magnetic resonance imaging (MRI; Figure 2) scans were requested.

Figure 1.

Computed tomography (CT) scan with contrast showing a well-defined extra-axial right cerebellar pontine angle densely enhancing 2.3 cm mass with intracanalicular extension in the right internal auditory canal keeping with right acoustic schwannoma (red arrow).

Figure 2.

Magnetic resonance imaging images (A) axial section and (B) coronal section showing right vestibular schwannoma mainly based in the right cerebellar pontine angle with intracanalicular extension. The scan demonstrating significant compression on the right trigeminal nerve and slight compression on the brainstem (red arrow).

Scans showed evidence of right CPA lesion with trigeminal nerve compression. The imaging characteristics is suggestive of acoustic neuroma. Patient was referred to a tertiary center for further treatment, where a follow-up scan was performed which demonstrated an increase in the tumor size by 3 mm over a period of 8 months. After being discussed in the multidisciplinary meeting, surgery was offered to the patient due to his young age, severity of symptoms, and the progression of the tumor. Patient underwent subtotal excision of the lesion by translabyrinthine approach by the neurosurgery and otology teams. He developed right facial and abducent nerves palsy with the expected hearing loss postoperatively. Histopathology results confirmed the diagnosis of schwannoma—World Health Organization grade 1 and genetic testing for neurofibromatosis type 2 was negative. Patient was referred to physiotherapy for facial nerve palsy rehabilitation and bone anchored hearing aid. Currently, he is still under regular follow-up and the 1-year postoperative MRI scan showed no change in the size of the residual disease.

Intracranial tumors, including CPA lesions, are one of the possible causes of trigeminal neuralgia. Acoustic schwannoma accounts for approximately 80% to 90% of the CPA tumor, ¹ which can present with altered facial sensation like pain or numbness. At the same time, approximately 1% of the patients who complain of orofacial pain ² and 6% to 16% of trigeminal neuralgia cases are secondary to intracranial tumors. ³

The clinical importance of this case is not originating from the rarity of the disease but from the popularity of the patients who may present with similar symptoms. It is not uncommon for those patients to be underinvestigated and dismissed with other nonspecific diagnosis, missing the important opportunity of the early diagnosis which in turn associated with less invasive treatment, better outcome, and less complications.

The pain in similar cases is neuropathic in nature and it usually described as a sudden, sharp, localized, and electric shock like sensation. This is secondary to the tumor that compresses the cranial nerves roots, and the severity increases with the progressive increase of the tumor size. Due to the limited clinical findings at the early stages of the disease and the slow growth of similar tumors, these patients may be underinvestigated and misdiagnosed with different disorders like temporomandibular, dental, paranasal sinuses, salivary glands diseases, and neurological conditions like migraine and trigeminal neuralgia.

Therefore, in patients with unilateral facial pain, detailed history of the nature and distribution of the pain is essential for further management and investigations. Intracranial tumors need to be ruled out when there is no obvious clinical cause of the presenting symptoms, regardless of patient age, by using radiological imaging like CT and MRI scans.