Evaluation of Very-High-Frequency Ultrasound Imaging Characteristics of Dermatofibroma.

Background: Dermatofibroma (DF) is one of the common dermatosis, which is so challenging to diagnose that its misdiagnostic incidence is quite high. The very-high-frequency (VHF) ultrasound is particularly relevant to the diagnosis of DF. Herein, we analyze the sonographic features and application value of VHF ultrasound in the diagnosis of DF.

Methods: Clinical data from 153 patients with pathologically confirmed DF from January 2019 to December 2023 were retrospectively analyzed using high-resolution VHF ultrasound, including size, location, shape, edge, boundary, interior echo, blood supply and so on.

Results: The VHF sonographic features of DF showed that the maximum diameter of the lesions was about 7.29 ±2.85 mm (mean ± standard deviation). In addition, most lesions were located in the middle and lower part of dermis (49%), with ill-defined (84%) and irregular shape (51%), 19% of which were serrated. Forty-four percent of lesions were hypo-echoic and heterogeneous, and 8% were complicated with calcifications. Nineteen percent of lesions presented as thickened dermal epidermal junction. Dermatofibroma are mostly hypovascular on color Doppler ultrasound. Forty-three percent of lesions were detected with punctate dotted blood flow signals. The correlation analysis showed blood flow classification and maximum diameter were not relevant.

Conclusion: The DF based on VHF ultrasonographic findings is characteristic, such as <10mm, ill-defined, located in the dermis, thickened DEJ, serrated shape, punctute or no flow on Doppler, which provide crucial indicators for differential diagnosis, potentially reducing the rate of DF misdiagnosis.