Ultrasound Pattern of Congenital Smooth Muscle Hamartoma of the Skin

Smooth muscle hamartoma (SMH) of the skin is a cutaneous benign proliferation of mature smooth muscle. Congenital SMH (CSMH) of the skin represents the most frequent type, and to date, there are no reports on its ultrasonographic pattern. A retrospective study of the color Doppler ultrasound (US) images of six CSMH patients at high and ultra-high frequencies was performed. Demographic data and US characteristics were analyzed. All cases presented a focal area of dermal thickening, decreased dermal echogenicity, and/or distorted dermal regions with prominent hair follicles. A total of 83.3% of cases showed no signs of internal vascularity at color Doppler imaging. Ultrasonographic features can support clinical diagnosis and follow-up of CSMH, which may potentially avoid biopsies.