Calcifying epithelioma of malherbe (Pilomatrixoma): Clinical and sonographic features

PURPOSE The purpose of this study was to describe the clinical and sonographic features of calcifying epitheliomas (pilomatrixomas). METHODS We retrospectively reviewed the clinical data and sonographic appearances of 59 cases of calcifying epitheliomas in 58 patients that were confirmed pathologically. RESULTS The mean age of the patients was 26 years (range, 5-69 years) and the female-to-male ratio was 1.2. All masses were located in subcutaneous soft tissues. Overall, 76.3% of the cases were located in the head and neck; the mean tumor size was 13 mm, and 72.9% of the cases were between 10 and 20 mm in size. Of the lesions, 62.7% were hypoechoic masses with internal calcifications, and 74.6% of them showed low or moderate internal vascularity on Doppler imaging. CONCLUSIONS The diagnosis of calcifying epithelioma should be considered in a patient with a painless, circumscribed, oval-shaped hypoechoic mass with internal calcifications and internal vascularity in the subcutaneous soft tissues of the head or neck. The mass may be small and have well-defined margins, with hypoechogenicity. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:3-7, 2018.