Introduction: Schwannomas are encapsulated tumors of the peripheral nervous system, composed of Schwann cells in a collagen matrix[1]. They are considered the most frequent benign tumors of peripheral nerves[2]. Those located in the sciatic nerve correspond to less than 1% of the schwannomas[3]. They appear generally without association with genetic causes, although similar histologies can occur in patients with neurofibromatosis[1,2,4,5]. Due to its slow growth, neurological functions are usually intact[2]. However, as they grow and compress nerves, they can trigger radiated pain, paresthesia and motor symptoms[1]. Although Magnetic Resonance Imaging (MRI) is considered the gold standard for diagnosis, ultrasonography can still be used to identify these tumors[2]. When symptomatic, management is based on surgical intervention[4].
Methods: This is a case report of patient with Neurofibromatosis type 2 (NF2) diagnosed with a tumor in the tibial segment of the left sciatic nerve.
Results: Clinical case: 63-year-old man, history of NF2, with complaint of pain in the posterior aspect of the left thigh in the path of the ipsilateral sciatic nerve. MRI identified the presence of a probable schwannoma in this nerve. Surgical intervention was proposed and tumor excision with nerve root preservation was performed, with the aid of intraoperative ultrasonography for better localization and approach. During the immediate postoperative period, he presented paresis on the dorsiflexion of the left foot with a slight improvement the following day. Histopathologic result confirmed schwannoma type of A of Antoni.
Conclusions: Although uncommon, schwannoma of the sciatic nerve should be considered as a differential diagnosis for patients with chronic sciatica, with no back pain or signs of root compression in imaging tests, especially in patients with neurofibromatosis. It was evidenced that the use of intraoperative ultrasound facilitates the approach and contributes to better aesthetic results of this procedure.
Patient Care: The ultrasound facilitates the approach and contributes to better aesthetic results of this procedure.
Learning Objectives: Case Report
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2. Navarro NN, Sola RAS, Belsuzarri TAB, Marques RMB, Araujo JFM. Schwannomas of peripheral nerves: unusual cause of sciatic and literature review. Arq Bras de Neurocirurgia. 2015; 35:195-9.
3. Wolock BS, Baugher WH, McCarthy EJ. Neurilemoma of the sciatic nerve mimicking tarsal tunnel syndrome. Report of a case. J Bone Joint Surg Am 1989;71:932-4.
4. Rosser T. Neurocutaneous Disorders. Continuum (Minneap Minn). 2018 Feb;24(1, Child Neurology):96-129.
5. Figueiredo AC, Mata-Machado N, McCoyd M, Biller J. Neurocutaneous Disorders for the Practicing Neurologist: a Focused Review. Curr Neurol Neurosci Rep. 2016 Feb;16(2):19.