Department of Radiology, College of Medicine, Ewha Womans University, Korea.
Published online: January 1, 2001.
ABSTRACT
PURPOSE: To investigate the sonographic features including color Doppler pattern of pilomatrixoma in children MATERIALS and METHODS: we retrospectively reviewed the ultrasonographic features of 11 patients (M:F = 9:2) who had pathologically proven as pilomatrixoma for 5 years . Their age ranged from 1 to 11 years (average : 4.3 years old). Imaging was performed under a 7 MHz linear transducer and color Doppler ultrasonography was additionally performed in 9 cases. The analysis of ultrasonographic features was focused on the lesion's location, shape, size, and margin of mass, internal echogenicity and periphery of mass, calcification, and the color Doppler signal. On the color Doppler examination, we assessed the Doppler signals inner and outer portions of mass. RESULTS: The masses were detected in the cheek (n = 5), preauricular area (n = 3), eyebrow (n = 1), zygomatic area (n = 1), and submandibular area (n = 1), and all were localized within the subcutaneous fat layer. All masses were oval shaped and their sizes were measured as 3.6-15.2 x 7.0-22.9mm. The margin of masses was well-defined in 10/11 (91%) and ill-defined in 1/11 (9%). Internal echogenicity of all masses was hypoechoic, which was heterogeneous in 8/11 (73%) or homogeneous in 3/11 (27%). Posterior shadowing was seen in 7/11 ( 6 4 % ) . Hypoechoic rim (thickness: 0.4-1.9 mm) was visualized in 7/11 (64%). In one Doppler examination, color Doppler flow signals were observed in the inner portion of the masses in 4/9 (44%) and outer portion of the masses in 7/9 (78%). CONCLUSION: The sonographic features of pilomatrixoma are hypoechoic mass with well-defined margin and calcification within the subcutaneous fat layer. Color Doppler signals can be observed in the inner and/or outer portion of the pilomatrixoma.