Pilomatrixomas, also called pilomatricomas or calcifying epitheliomas of Malherbe, are common benign cutaneous tumors that affect children and young adults and arise from the hair follicle matrix. Clinical misdiagnosis has been reported in up to 56% of the cases. Sonography can support the diagnosis and the classical and most frequent morphology is a round or oval shaped nodule with hypoechoic rim and hyperechoic center. The hyperechoic spots in the center correspond to calcium deposits,which can be a key for diagnosing pilomatrixomas. There are another less frequent sonographic patterns (variants) of pilomatrixomas such as hypervascular and cystic. References 1-Pilomatricoma in children: common but often misdiagnosed. Acta Chir Belg. 2010;110:250-254. 2-The common ultrasonographic features of pilomatricoma. J Ultrasound Med. 2005;24:1397-1402. 3-Pilomatricomas: the diagnostic value of ultrasound. Skeletal Radiol. 2010;39:243-250. 3-Common applications of dermatologic sonography.J Ultrasound Med. 2012 Jan;31(1):97-111. 4-Pilomatrixomas presenting as vascular tumors on color Doppler ultrasound.J Pediatr Surg. 2010 Oct;45(10):2094-8.
Clinical image.3 y-o child with a slighly erythematous and painless lump (arrows) in the left aspect of the neck.
Ultrasound (grey scale, transverse view, left aspect of the neck) shows oval shaped nodule located in the dermis and subcutaneous tissue with hypoechoic rim and hyperechoic spots (arrowheads). Abbreviations: d, dermis; st, subcutaneous tissue; r, rim
Ultrasound ( color Doppler, transverse view, left aspect of the neck) demonstrates a few vessels in the periphery of the nodule (*)
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