Korean J Dermatol.  2022 May;60(4):228-234.

The Importance of Ultrasonography in the Diagnosis of Epidermal Cysts and Lipomas in the Field of Dermatology

• Shin K
• Won SH
• Park C
• Kim GW
• Kim HS
• Ko HC
• Kim MB
• Kim BS

Abstract

Background
Ultrasonography (US) is a simple and reliable tool that can aid in the diagnosis of benign subcutaneous lesions such as epidermal cysts and lipomas.
Objective
This study aimed to determine the efficacy of US for the differential diagnosis of epidermal cysts and lipomas.
Methods
A retrospective study of 100 patients with epidermal cysts (n=45) or lipomas (n=55) who underwent US and then received a pathological diagnosis in the dermatology department of Pusan National University Hospital was conducted.
Results
US and clinical impressions accurately diagnosed the epidermal cysts in 90.0% and 88.0% of the patients, respectively, and the lipomas in 92.0% and 88.0% of the patients, respectively. US combined with clinical impression significantly increased the diagnostic yield of epidermal cysts (98%) and lipomas (99%). On US, the frequency of posterior acoustic enhancement was higher for the epidermal cysts than for the lipomas (82.2% and 29.1%, respectively; p＜0.001), and striated echoes such as internal linear echogenic reflections and dark clefts were more frequently found in the lipomas than in the epidermal cysts (90.9% and 6.7%, respectively; p＜0.001).
Conclusion
This study implies that the diagnostic role of US can be greatly enhanced by knowledge of the clinical presentation.

Keyword

Epidermal cyst; Histology; Lipoma; Ultrasonography