Hybrid schwannoma-neurofibroma of the upper cervical spine: illustrative case and systematic review of spinal hybrid nerve sheath tumors.

BACKGROUND

Hybrid peripheral nerve sheath tumors (HPNSTs) are rare benign neoplasms characterized by the coexistence of multiple peripheral nerve sheath lineages, most commonly schwannoma, neurofibroma, and perineurioma. Although increasingly recognized as a distinct pathological entity, spinal involvement remains exceedingly uncommon, posing diagnostic and therapeutic challenges.

METHODS

A systematic review was conducted in accordance with PRISMA guidelines using PubMed, Scopus, and Web of Science from database inception to April 2026. Studies reporting histologically confirmed primary spinal HPNSTs were included. Demographic, clinical, radiological, histopathological, immunohistochemical, and outcome data were extracted and descriptively analyzed.

CASE DESCRIPTION AND LITERATURE

RESULTS

A 25-year-old male presented with a 3-month history of progressive cervical and left shoulder pain accompanied by intermittent numbness. Magnetic resonance imaging revealed a dumbbell-shaped intradural extramedullary lesion at the C1-2 level with foraminal extension and cervical cord compression. Gross total microsurgical resection was achieved through a C1-C2 interlaminar microsurgical approach. Histopathological examination demonstrated a biphasic neoplasm composed of hypercellular schwannomatous nodules and hypocellular neurofibromatous areas within a collagenous and myxoid stroma. Immunohistochemistry revealed diffuse SOX10 positivity within the schwannian component and prominent CD34 reactivity in the neurofibromatous stroma, confirming a hybrid schwannoma-neurofibroma (WHO grade 1). The patient remained neurologically intact without recurrence at 20-month follow-up. Five eligible studies comprising nine spinal HPNST cases were identified. Schwannoma-perineurioma represented the predominant subtype (66.7%), whereas schwannoma-neurofibroma tumors accounted for (33.3%) of cases. Gross total resection was generally associated with favorable outcomes, while recurrence was rarely reported.

CONCLUSION

Spinal HPNSTs are exceptionally rare lesions that remain difficult to diagnose preoperatively because of nonspecific radiological features. Definitive diagnosis relies on histopathological and immunohistochemical confirmation, whereas gross total resection appears to provide favorable outcomes.