Polyp

A polyp is a projecting growth from the lining of an organ or body cavity, typically arising from a mucous membrane. In ultrasound, polyps are most commonly encountered in the gallbladder and the endometrium (uterine lining). Gallbladder polyps appear as echogenic projections from the gallbladder wall that do not cast an acoustic shadow and do not move with changes in patient position — features that help distinguish them from gallstones. Endometrial polyps appear as focal thickenings within the endometrial stripe, sometimes with a feeding vessel visible on color Doppler. Most polyps are benign, but larger polyps or those with atypical features may warrant further evaluation or removal due to a small risk of malignancy.