Imaging characteristics of orbital peripheral nerve sheath tumors: Analysis of 34 cases

BACKGROUND: Peripheral nerve sheath tumors (PNSTs), a rare group of neoplasms in the orbit, comprise only 4% of all orbital tumors. At present, there are very few studies detailing the features of these tumors identified using imaging technology. AIM: To compare the differences in location, morphology, magnetic resonance imaging (MRI) signal intensity/computed tomography (CT) value, and enhancement degree of tumors of different pathological PNSTs types. METHODS: Clinical, pathological, CT, and MRI data were analyzed retrospectively in 34 patients with periorbital sheath tumors diagnosed using histopathology from January 2013 to August 2021. RESULTS: Among 34 cases of orbital peripheral nerve sheath tumors, 21 were schwannomas, 12 were neurofibromas, and 1 was a plexiform neurofibroma. Common clinical symptoms presented by patients with these types of tumors include eyelid swelling, exophthalmos, and limited eye movement. Schwannomas mostly occur in the intramuscular space with small tumor volume and rare bone involvement. Neurofibromas develop in the extrapyramidal space with larger tumor volume and more bone involvement. Radiologically, schwannomas and neurofibromas are characterized by regular morphology and uneven density and signal. One case of plexiform neurofibroma showed tortuous and diffuse growth along the nerve, with a worm-like appearance on imaging. CONCLUSION: Different pathological types of orbital peripheral nerve sheath tumors have unique imaging characteristics. Comprehensive consideration of the patient's clinical and imaging manifestations is of great value in the diagnosis of orbital peripheral nerve sheath tumors.