Relationship between sonographic and pathologic findings in epidermal inclusion cysts.
OBJECTIVE
We evaluated the sonographic findings in epidermal inclusion cysts and related them to the pathologic findings.


METHODS
We retrospectively reviewed the sonograms and pathology specimens of 24 patients with pathologically proven epidermal inclusion cysts. We evaluated the lesions for shape, size, internal echogenicity, posterior sound enhancement, and presence of color Doppler signals. We classified the masses into 5 sonographic types according to their internal echogenicity. The relationship between the sonographic types and the pathologic findings was examined.


RESULTS
The masses were ovoid or spherical in 17 cases (71%), lobulated in 5 (21%), and tubular in 2 (8%). The longest diameter ranged from 1 to 6 cm (mean, 3.1 cm). Twenty-three cases (96%) were associated with posterior sound enhancement. Color Doppler signals were absent in 20 cases, but some vascularity was noted in 4 ruptured epidermal cysts, in areas of granulation tissue. The most common sonographic type was a hypoechoic lesion with scattered echogenic reflectors (10 cases). Sonographic findings were related to the lamellation of keratin debris and the granulation tissue secondary to rupture. Most cases with a lobulated configuration (4 of 5) or color Doppler signals (4 of 4) were ruptured cysts.


CONCLUSIONS
Epidermal inclusion cysts most often appeared sonographically as a hypoechoic mass containing variable echogenic foci without color Doppler signals. Ruptured epidermal cysts, however, may have lobulated contours and show color Doppler signals, mimicking a solid mass.
Lee
H S
HS
Department of Diagnostic Radiology, College of Medicine, Hanyang University, 17, Haengdang-Dong, Seungdong-Gu, Seoul 133-792, South Korea.
Joo
K B
KB
Song
H T
HT
Kim
Y S
YS
Park
D W
DW
Park
C K
CK
Lee
W M
WM
Park
Y W
YW
Koo
J H
JH
Song
S Y
SY
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D004814:Epidermal Cyst / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012421:Rupture; D018615:Ultrasonography, Doppler, Color