Pilomatricomas in children: imaging characteristics with pathologic correlation.
BACKGROUND
Although pilomatricoma commonly occurs in children, there is still a poor understanding of the imaging characteristics of pilomatricoma and lack of agreement regarding its imaging findings and histopathologic features.


OBJECTIVE
To characterize the radiologic appearance of pilomatricomas on US, CT, and MR and to correlate the imaging findings with histopathologic features.


METHODS
The imaging findings of 47 pilomatricomas on US (n = 17), CT (n = 31), and MR (n = 5) were retrospectively evaluated. Pathologic specimens of all cases were reviewed and compared with imaging findings.


RESULTS
All lesions were well-circumscribed, subcutaneous nodules with partial attachment to the overlying skin. On US, the lesions were mostly hyperechoic with posterior acoustic shadowing and hypoechoic rim. On CT, they appeared as enhancing soft-tissue masses with varying amounts of calcification. MR findings were internal reticulations and patchy areas on T2-weighted images and contrast-enhanced T1-weighted images, corresponding to edematous stroma on pathology. Peritumoral inflammatory changes and connective capsule on pathology were well correlated with imaging findings.


CONCLUSIONS
Pilomatricoma should be considered when US or CT shows a well-defined hyperechoic or calcific nodule in subcutaneous fat attached to the skin in children. MR images may be helpful in diagnosis. Pathologic findings are well correlated with imaging findings.
Lim
Hyun Wook
HW
Department of Radiology, Kangnam St. Mary's Hospital, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul 137-701, South Korea.
Im
Soo Ah
SA
Lim
Gye-Yeon
GY
Park
Hyun Jin
HJ
Lee
Heejeong
H
Sung
Mi Sook
MS
Kang
Bong Joo
BJ
Kim
Jee Young
JY
D000293:Adolescent; D002648:Child; D003287:Contrast Media; D003937:Diagnosis, Differential; D005260:Female; D019786:Gadolinium DTPA; D006201:Hair Diseases / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D018296:Pilomatrixoma / Q000175:diagnosis* / Q000473:pathology; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000175:diagnosis* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
D003287:Contrast Media; D019786:Gadolinium DTPA