Neurinom

Neurinom, also known as neurinoma or schwannoma, is a benign tumor arising from Schwann cells that form the protective sheath around nerves. It most often develops along cranial or spinal nerve roots and is typically solitary. The growth is usually slow and the lesion is well circumscribed, which can facilitate surgical removal. A minority of cases occur in people with neurofibromatosis type 2, but most neurinoms are sporadic.

Localization and presentation vary with the involved nerve. The most common cranial site is the vestibulocochlear nerve, where the tumor is often referred to as an acoustic or vestibular schwannoma; patients may experience unilateral sensorineural hearing loss, tinnitus, or balance problems. Schwannomas of trigeminal, facial, or other cranial nerves cause corresponding sensory or motor symptoms. Spinal neurinomas arise from spinal nerve roots and can cause localized back or radicular pain, numbness, or weakness if they compress adjacent structures.

Pathologically, neurinoms are composed of Schwann cells and are typically encapsulated. Histology shows alternating hypercellular (Antoni A) and hypocellular (Antoni B) areas, with strong positivity for S-100 protein on immunohistochemistry.

Diagnosis relies primarily on magnetic resonance imaging with contrast, which reveals a well-defined, nerve-associated enhancing mass. Computed tomography can aid in assessing bone changes when a skull base or foraminal lesion is involved. Treatment ranges from observation for small, asymptomatic tumors to microsurgical excision with nerve-sparing techniques; stereotactic radiotherapy is an option for some patients or when surgery carries high risk. Prognosis is generally favorable, with long-term control in most cases, though recurrence can occur after subtotal resection.