Pediatric intradural-extramedullary spinal schwannoma: A case of acute coxalgia

An 11-year-old girl experienced nocturnal right coxalgia, progressing to lumbosacral spine pain and walking difficulties. Despite negative inflammatory markers, she displayed joint limitations, lumbar tenderness, and abnormal patellar reflexes. Neurological examination revealed mobile right hip, with pain during Mingazzini II manoeuvre. The clinical presentation defied specific diagnoses, posing a diagnostic challenge.

Following an inconclusive pelvic X-ray and a non-diagnostic pelvic MRI, a basal lumbosacral MRI was pursued due to persistent symptoms. This examination revealed an intradural oval mass located posterior to the T12 vertebra with a craniocaudal extension of 30 millimetres. The mass exhibited a distinctive regular shape, encompassing the entire canal and consisting of solid components interspersed with cystic areas. Notably, it caused lateral and contralateral displacement of the medullary cone and exerted pressure on the emerging roots without invading neighbouring bony structures (Figures 1 and 2).

Subsequently, the patient was transferred to the Pediatric Neurosurgery department, where a contrast-enhanced MRI raised suspicion of a spinal neurinoma at the L2 level, marked by heterogeneous enhancement of the non-cystic portions of the mass (Figure 3). These imaging findings collectively provided valuable insights for guiding the patient's diagnosis and subsequent surgical intervention.

Background

Spinal schwannomas, also known as neurinomas, are predominantly benign tumours originating from the spinal nerve root sheaths. These slow-growing masses arise from well-differentiated Schwann cells, essential for myelin production and neuronal function [3,4]. Typically oval or round, these tumours are encapsulated and lobulated, arising eccentrically from nerve root sheaths. They exhibit a slow growth rate, expanding by 2.3% to 5.3% in volume annually [5]. These primary spinal tumours are rare, constituting only 4-6% of all central nervous system neoplasms, with an incidence peak in the fourth to fifth decades of life [6,7]. Schwannomas generally occur as solitary masses, while multiple schwannomas are often linked to neurofibromatosis type II (NFII) [8,9]. About 80% of pediatric spinal schwannomas localize intradurally, involving dorsal sensory nerve roots [10]. Symptoms vary based on the tumour's location, size, and involvement of surrounding structures, often manifesting as nocturnal radicular pain or signs of nerve root or spinal cord compression [4]. Severe cases can lead to lower limb weakness and walking difficulties.

Clinical Perspective

Clinical manifestations of spinal schwannomas are nonspecific, leading to delayed diagnoses due to the slow progression of symptoms. In our case, an 11-year-old girl presented with atraumatic right coxalgia progressing to lumbosacral pain and walking difficulties, necessitating imaging to elucidate the underlying cause. The inconclusive nature of neurological symptoms underscores the importance of precise diagnostic tools for accurate identification.

Imaging Perspective

High-resolution MRI, incorporating sagittal and axial images post-gadolinium injection with T2-T1 weighted, GRE, DWI, and FLAIR sequences, serves as the cornerstone for diagnosing spinal schwannomas. Intradural schwannomas appear as well-circumscribed, homogeneous nodular masses, iso-/hyperintense at T1 and hyperintense at T2, often originating from dorsal sensory nerve roots. The presence of cystic portions within larger schwannomas might result in hyperintense areas on T2WI. Contrast-enhanced MRI aids in highlighting non-cystic components, crucial for diagnosis confirmation [12,13].

Outcome

Surgical excision remains the primary treatment for spinal schwannomas. Minimally invasive approaches, when applicable, ensure effective symptom resolution. However, complications such as sphincter dysfunction and persistent back pain might arise post-surgery [14].

Take Home Message / Teaching Points

Pediatric spinal schwannomas, although rare, can cause significant morbidity. In cases of nonspecific neurological symptoms, prompt and accurate diagnosis via high-resolution MRI is pivotal for timely intervention. Minimally invasive surgical techniques, guided by precise preoperative planning, offer favourable outcomes, emphasizing the critical role of imaging in the management of these tumours.

All patient data have been completely anonymized throughout the entire manuscript and related files