Extracranial and extraspinal nerve sheath tumors: computed tomographic evaluation

Area of Science:

• Radiology
• Oncology
• Neurology

Background:

• Peripheral nerve sheath tumors (NST) are neoplasms arising from the nerve sheath.
• Accurate pre-operative characterization of NST is crucial for treatment planning.
• Computed tomography (CT) is a key imaging modality for evaluating soft tissue masses.

Purpose of the Study:

• To evaluate the CT features of various types of peripheral nerve sheath tumors.
• To identify distinguishing CT characteristics between benign (schwannomas, neurofibromas) and malignant NST.
• To assess the diagnostic accuracy of CT in pre-operative NST evaluation.

Main Methods:

• Retrospective analysis of CT scans from 35 patients with 37 peripheral nerve sheath tumors.
• Categorization of tumors into schwannomas, neurofibromas, plexiform neurofibromas, diffuse neurofibromas, and malignant NST.
• Detailed assessment of tumor morphology, margins, and enhancement patterns on contrast-enhanced CT.

Main Results:

• Benign NST typically presented as well-defined masses with displacement of adjacent structures.
• Neurofibromas and plexiform neurofibromas were more frequently homogeneously hypodense on contrast-enhanced CT compared to schwannomas.
• Poorly defined margins were the most reliable indicator of malignancy in NST.
• CT allowed for pre-operative diagnosis or differential diagnosis in 92% of cases.

Conclusions:

• CT imaging demonstrates characteristic features that can help differentiate benign from malignant peripheral nerve sheath tumors.
• Differences in CT enhancement patterns between schwannomas and neurofibromas may reflect variations in vascularity and blood-nerve barrier.
• Contrast-enhanced CT is a valuable tool for the pre-operative assessment of peripheral nerve sheath tumors, improving diagnostic accuracy.