Characterization of dermatofibromas and epidermoid cysts using dermoscopy-guided high-frequency ultrasound imaging

Epidermoid cysts and dermatofibromas may resemble malignant lesions, requiring accurate non-invasive differentiation. Our objective was to assess dermoscopy-guided high-frequency ultrasound (DG-HFUS) in distinguishing these lesions.

Nine lesions (four epidermoid cysts, five dermatofibromas) were examined using DG-HFUS with a 33 MHz linear probe in B-mode. The dermoscopic modality guided probe placement. For each lesion, a minimum of 10 consecutive frames were acquired to ensure measurement reproducibility. Lesions were evaluated based on predetermined characteristics.

Epidermoid cysts presented as well-circumscribed, oval lesions located in the dermis or dermal-subcutaneous border, with depths of 1.4-8.7 mm. All showed mixed echogenicity with hyperechoic foci and bands. Dermatofibromas were smaller (2.4-3.5 mm), within the dermis, hypoechoic with scattered hyperechoic areas, poorly defined margins, and 3-5 hypoechoic bands extending into surrounding structures.

DG-HFUS reliably correlated dermoscopic and sonographic features, enhancing non-invasive diagnosis of benign cutaneous lesions.