Peripheral nerve schwannomas: Anatomical distribution, biopsy risks and surgical outcomes in a contemporary large-volume case series

Abstract

Background: Schwannomas are benign peripheral nerve sheath tumours that may cause pain, sensory disturbance and functional deficits. Despite their typically indolent nature, management decisions carry the risk of neurological morbidity. This study presents the largest single-centre series of schwannomas reported to date, evaluating clinical presentation, imaging, management and outcomes.

Methods: A retrospective review was conducted of solitary schwannomas treated at a tertiary peripheral nerve injury unit between 2017 and 2020. Data collected included anatomical location, imaging features, preoperative biopsy status, surgical outcomes and histological subtype. Statistical analysis compared tumour volume by anatomical location and postoperative neurological outcomes based on biopsy status.

Results: Overall, 531 solitary schwannomas were identified. Schwannomas were distributed throughout the body (50.0% lower limb, 40.5% upper limb and 9.5% trunk). Proximal limb schwannomas were significantly larger than distal ones (p=0.015; t-test). Preoperative biopsy was performed in 38% of cases and was associated with a higher risk of postoperative neurological symptoms (RR 1.36; 95% CI 1.06 to 1.74; p=0.043). Surgical excision was performed in 89.6% of cases. Variant histological subtypes identified included ancient, plexiform, hybrid, melanotic and microcystic/reticular schwannomas.

Conclusions: Schwannomas can present at any peripheral nerve site but are typically larger proximally. Preoperative biopsy increases the risk of neurological morbidity and should be reserved in cases where malignancy is suspected. Microsurgical enucleation at specialist centres provides excellent outcomes. This series provides the most detailed contemporary description of solitary schwannomas and informs best practice management guidelines.

Level of evidence: Level IV, retrospective case series.

Keywords: Biopsy; Neurological complication; Peripheral nerve tumour; Schwannoma; Surgical outcomes.