The difference between cysts and lipomas lies in the nature of their contents, the site of occurrence, and the difference in imaging manifestations. 1. The nature of the contents: the contents of cysts are mostly liquid substances, and in the case of sebaceous cysts, they are mostly tofu scum-like substances; whereas the contents of lipomas are fat particles. 2. Site of occurrence: cysts can occur in various tissues and organs of the whole body, such as liver cysts, tenosynovial cysts, renal cysts, sebaceous cysts, etc. Lipomas preferably occur in the limbs, trunk, or inter-visceral adipose tissues, with clear boundaries, and can be lobulated. 3. Imaging performance: cysts are characterized by anechoic areas; lipomas are characterized by hypoechoic areas. The difference between cysts and lipomas should be consulted with clinicians. If cysts or lipomas are present, clinicians should be consulted and medical advice should be followed for observation or surgical resection.