Objective: To evaluate the contribution of ultrasonography in the diagnosis of neurilemmoma and to establish if a round or round-like shape adds useful information for ultrasonographic diagnosis.
Methods: Archives of ultrasound findings in 203 patients (127 males and 76 females, aged 14 -72 years old, mean 32.1 +/- 25.8) with limb mass were reviewed. The maximal and minimal diameter of the lesions was 78 mm and 11 mm, respectively (mean 34.7 +/- 15.6 mm). Lesions' morphology, size, capsule, and relationship with the adjacent nerve were analyzed, round-like or round shaped was focused, ratio of longitudinal maximal diameter and short maximal diameter (L/S) was calculated. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of ultrasonographic diagnosis were determined.
Results: In 37 patients with ultrasonographic suspicion of neurilemmomas, the neurilemmomas were confirmed in 31 cases. From 166 patients with tumors presumed as being non-neurilemmoma lesions, 18 cases in the final diagnosis were neurilemmomas. Ultrasound had 63.3% sensitivity, 86.0% specificity, 56.4% positive predictive value, 89.2% negative predictive value, and 80.9% accuracy for the diagnosis of neurilemmoma. Round-like or round shaped and L/S diameters ratio were not specific for neurilemmomas ultrasonographic appearance (P > 0.05).
Conclusion: Ultrasound can diagnose neurilemmomas with high accuracy, but the round or round-like shaped and L/S diameters ratio have little value in ultrasonographic identification of neurilemmomas of the limbs.