Skeletal Radiology

, Volume 40, Issue 11, pp 1415–1419

Subcutaneous epidermal inclusion cysts: Ultrasound (US) and MR imaging findings

  • Hee Kyung Kim
  • Sung Moon Kim
  • Sang Hoon Lee
  • Judy M. Racadio
  • Myung Jin Shin
Scientific Article

DOI: 10.1007/s00256-010-1072-4

Cite this article as:
Kim, H.K., Kim, S.M., Lee, S.H. et al. Skeletal Radiol (2011) 40: 1415. doi:10.1007/s00256-010-1072-4

Abstract

Objective

To describe the characteristic US and MR findings of subcutaneous epidermal inclusion cysts.

Materials and methods

Seventy-nine patients with subcutaneous epidermal inclusion cysts underwent US (n = 70), MR (n = 7), or both (n = 2). On US, the margin, shape, echogenicity, through-transmission, wall, internal debris and vascularity were evaluated. On MR, the shape, wall, signal intensity, internal debris, and enhancement pattern were evaluated.

Results

On US, characteristic findings were well circumscribed (n = 69, 96%), ovoid-shaped (n = 56, 78%), heterogeneously and mildly echogenic (n = 66, 92%), increased through-transmission (n = 66, 92%) and low echoic rim (n = 48, 67%). Internal debris was seen in 31 cases (43%) and often contained linear echogenic reflections (n = 12, 17%), dark clefts (n = 13, 18%), or a mixture (n = 5, 7%). Most masses showed no Doppler flow (n = 70, 97%). On MR, all cases demonstrated a well-demarcated oval-shaped mass with a surrounding rim. On T1-weighted image (WI), the mass showed slightly high T1 signal in 4/9 (44%) and iso-signal in 5/9 (56%). On T2WI, the mass showed high signal in 6/9 (67%), intermediate in 2/9 (22%), and a target appearance in 1/9 (11%). Internal linear dark T2 signal debris was observed in 4/9 (44%). All lesions showed peripheral rim enhancement without central enhancement.

Conclusions

On US, subcutaneous epidermal inclusion cysts are usually well-circumscribed, oval-shaped, mildly echogenic masses with occasional linear anechoic and/or echogenic reflections, increased through-transmission, hypoechoic rim and no Doppler flow. On MR, an intermediate to high T2 signal mass with occasional low signal debris and no central enhancement can strengthen the diagnosis.

Keywords

UltrasoundMREpidermal inclusion cyst

Copyright information

© ISS 2010

Authors and Affiliations

  • Hee Kyung Kim
    • 1
    • 2
  • Sung Moon Kim
    • 1
    • 3
  • Sang Hoon Lee
    • 1
  • Judy M. Racadio
    • 2
  • Myung Jin Shin
    • 1
  1. 1.Department of Radiology and Research InstituteUniversity of Ulsan College of Medicine, Asan Medical CenterSeoulKorea
  2. 2.Department of RadiologyCincinnati Children’s Hospital Medical CenterCincinnatiUSA
  3. 3.Department of RadiologyUniversity of Michigan HospitalsAnn ArborUSA