Pilomatricoma

Ultrasound imaging of pilomatricomas demonstrates lesions with an ovoid complex mass at the junction of the dermis and subcutaneous fat with focal thinning of the overlying dermis. 5 Pilomatricomas appear as target lesions with a hyperechoic rim (corresponding to the connective tissue capsule) and an echogenic center (corresponding to the central island of epithelial cells).5 Ultrasonography may also depict calcification.5 While ultrasound imaging may be helpful in diagnosis, it is not completely reliable.5 Computed tomography has also been used to investigate pilomatricomas. Most demonstrate uniform, homogeneous signal on T1 weighting, either low10, intermediate7 (similar to the appearance of skeletal muscle as in the case presented in this paper) or high.9 On T2 weighting the appearance of the lesions was variable: some are inhomogeneous with multiple areas of intermediate signal intensity (such as the case presented here);7,8,10 others are homogeneous with intermediate signal intensity7; and others exhibit high signal bands radiating from the center to a higher signal periphery.9 On T1 with contrast, some enhance,8,10 some do not7 and some only enhance peripherally.8 In this case there was patchy internal enhancement with intense peripheral enhancement.