To investigate the sonographic findings of schwannomas to improve its diagnostic accuracy.

We retrospectively analyzed 43 patients with schwannomas who underwent ultrasound examination at our hospital from June 2012 to September 2018. All of cases were confirmed by pathology. Sonographic findings, including tumor location, number, size, morphology, boundary, and internal echo were recorded. The relationship between the mass and nerves and surrounding tissues was observed. The blood supply of tumors was also recorded.

There were 43 cases of schwannoma, including 6 cases in the neck, 7 in the hands, 10 in the upper limbs, 3 in the armpits, 9 in the lower limbs, 5 in the foot, and 3 in the trunk. Most of the schwannomas were oval and solid, and had a clear boundary and less blood flow signal. The four characteristics on ultrasound images, including rat tail sign, target sign, entering-and-exiting-nerve sign, and vascular accompanying sign, significantly improved diagnostic accuracy. Only 20 cases were diagnosed correctly by ultrasound, and 23 cases were misdiagnosed, with a misdiagnosis rate of 53.5%.

High-frequency ultrasound has great diagnostic value in schwannomas.