Superficial lesions — typical appearance
| Lesion | US appearance |
|---|---|
| Lipoma | Oval, compressible, iso/hyperechoic, linear septa parallel to skin, minimal vascularity |
| Epidermal/sebaceous cyst | Well-defined subcutaneous, variable content (anechoic→solid), "submarine sign", posterior enhancement |
US for lipoma: sens. ~95% / spec. ~94%; epidermal cyst: sens. ~80% / spec. ~95%. Red flags (solid > 5 cm, chaotic vascularity, growth) → work up for tumor.
Source: SRU Consensus 2021 (Radiology) / KJR