What is the definition of spinal schwannoma?
Schwannomas, also known as neurinomas or neurilemmomas, are benign nerve sheath tumors that occur in the spinal canal and are composed primarily of Schwann cells of spinal nerve roots.
How are the clinical manifestations of spinal schwannomas?
Clinical presentation varies depending on the tumor location and involvement of the spinal cord and nerve roots. Patients with spinal schwannomas may present with pain, paresthesias, motor deficits, sphincter impairment, and myelopathy.
How are the histopathological characteristics of schwannomas?
Schwannomas are benign neoplasms of Schwann cells (WHO grade I). Their macroscopic appearance usually shows an encapsulated neoplasms, composed of epineurium, which develop as fusiform masses eccentrically from the nerve, with the nerve displaced to the periphery of the mass. Schwannomas are classified based on histological patterns as Antoni A and B types. Microscopic appearance of type Antoni A is characterized by spindle cells densely packed, arranged in short bundles or interlacing fascicles, and demonstrates palisading and Verocay bodies. The pattern Antoni type B has cells less, organized with areas of myxomatous and cystic degeneration. Malignant degeneration of schwannomas is very uncommon.
What are the MRI features of spinal schwannomas?
The majority of spinal schwannomas are intradural extramedullary in location; usually they appear as solid, well-defined, rounded lesions, often associated with adjacent bony remodeling. When large, they may align themselves with the long axis of the cord, forming sausage-shaped masses that can extend over several levels, as illustrated in the present case. They may also protrude out of the neural foramen, forming a dumbbell-shaped mass. On magnetic resonance imaging (MRI), the appearance of schwannomas is usually iso-to-hypointense on T1-weighted images, mostly are heterogenous hyperintense on T2, and diffusely enhancing on contrast-enhanced images. On MRI type Antoni A tumors tend to be small and homogeneous, while heterogeneous tumors tend to have higher proportions of type Antoni B.
What is the treatment for spinal schwannomas?
Surgical resection of the tumor is the treatment of choice. Radiotherapy can be a second-choice treatment in some specific cases – patients who are not good candidates for surgery, or recurrent tumors.
Pathology
Histology
Macroscopic description:
Intradural content/tumor.
This tissue is a Compact, irregular, elastic, brownish-brown tissue fragments with yellowish areas, measuring the most extensive 2.2 x 0.9 x 0.5 cm.
Microscopic description:
A neoplasm with the typical histologic features of schwannoma, with Antoni type A and Antoni type B areas.
Conclusion:
Intradural T11 – L3 tumor resection: Schwannoma.